2.1 The distribution of [p] and [pp] in Japanese

The current section briefly details the distribution of singleton [p] and geminated [pp] in Japanese. This language has six plosives: [p, t, k, b, d, g]. Among these plosives, the voiceless bilabial plosive [p] exhibits different behaviours in several aspects. First, this plosive is notably less frequent than the others (see Labrune Reference Labrune2012: §3.15). Second, its distribution differs across Japanese lexical strata (Yamato (native) words, Sino-Japanese words, foreign words, and mimetic words; see Itô & Mester Reference Itô, Mester and Goldsmith1995, Reference Itô, Mester and Tsujimura1999; Nasu Reference Nasu and Kubozono2015). As shown in (1a), there is no distributional restriction of [p] in foreign words (e.g., Itô & Mester Reference Itô, Mester and Goldsmith1995: 819; Labrune Reference Labrune2012: 61). As in (1b), mimetic words like reduplicated forms /C₁VC₂V-C₁VC₂V/ allow singleton [p] to occur in the stem-initial (C₁) position (see Nasu Reference Nasu and Kubozono2015: 261).

Meanwhile, the distribution of singleton [p] is restricted in Yamato words and Sino-Japanese words. It is allowed to occur only in the stem-initial position of the second member of compounds, as exemplified in (2).Footnote ² In Yamato words, [p] generally appears as an alternant of [h], and it almost always becomes geminated [pp], as in (2a) (Labrune Reference Labrune2012: 60). In Sino-Japanese compounding, illustrated in (2b), [h] alternates with [p], becoming geminated [pp], or singleton [p] after a moraic nasal (Labrune Reference Labrune2012: 61). Yamato words and Sino-Japanese words rarely begin with singleton [p], although a few exceptions are found in slang (e.g., peten ‘trickery’, pakuru ‘to filch’; Labrune Reference Labrune2012: 72).

2.2 A sound-symbolic [h]→[p] alternation

This section discusses a Japanese nicknaming pattern wherein [h] alternates with [p], as exemplified in (3) (Kumagai Reference Kumagai2019, Reference Kumagai2022). Example (3a), Paruru, is the nickname for Haruka Shimazaki, an ex-member of the Japanese girls’ idol group AKB48. In this nickname, the initial consonant [h] becomes [p], and the second mora [ru] is reduplicated. This type of reduplication is often observed in Japanese girls’ idol names (see Hashimoto Reference Hashimoto2016 and Kawahara et al. Reference Kawahara, Katsuda and Kumagai2019 for additional examples). Miporin, in (3b), is the nickname for the Japanese actress and singer Miho Nakayama. Attaching a suffix-like nonce word rin is another nicknaming pattern found in Japanese (e.g., Mari + rin → Maririn; Yosi + rin → Yosirin), which is not exclusive to feminine nicknames. Example (3c), Ripopo, is the nickname for Riho Miaki, an ex-member of another Japanese idol group, Yoshimotozaka46. In this nickname, [h] turns into [p], and [po] is reduplicated. The [h]→[p] alternation in (3) is often used for (cute) feminine names; thus, it is termed a sound-symbolic [h]→[p] alternation in the current study. This kind of alternation is treated here as an output–output mapping (McCarthy & Prince Reference McCarthy and Prince1995; Benua Reference Benua1997) between the surface forms of the base and the nickname, paralleling analyses of other common nicknaming patterns such as truncation.

In addition to the examples in (3), we can also find girls’ nicknames affixed with a suffix-like morpheme [piː]; for example, the Japanese actress and singer Noriko Sakai is nicknamed Noripii, in which the first two moras of her first name are compounded with [piː]. This example shows that even if the name does not contain an [h] that can alternate with [p], it can be made to sound cute by adding another morpheme containing [p]. This process can be termed a sound-symbolic [p]-addition.

There are some interesting characteristics specific to the nicknames in (3). First, singleton [p] can occur even in word-initial position, as exemplified in (3a). In addition, although Miho and Riho are standard Japanese feminine first names, their counterparts with [p] are attested only as nicknames; to the best of my knowledge, there is no person whose original name is Mipo or Ripo.

In addition to the sound-symbolic reason for the [h]→[p] alternation, the use of [p] in the nicknaming process is also motivated by functional aspects. As mentioned in the previous section, singleton [p] is a less frequent consonant in native and Sino-Japanese words. For this reason, the name to which the [h]→[p] alternation is applied is unlikely to merge with other existing words in Japanese, and so it avoids potential functional problems for speakers. Additionally, because this consonant is less frequent in official names, singleton [p] can function as a marker of nicknaming (Kohei Nishimura, p.c.).

2.3 A nicknaming pattern using ‘princess’, pime-yobi and a challenging issue

This section describes a Japanese nicknaming pattern sometimes called pime-yobi ‘princess-calling’. Recently, blogs and articles on social media written in Japanese have displayed a new kind of nicknaming pattern using the word hime ‘princess’, as exemplified in (4), wherein the initial consonant [h] becomes [p] when the word is attached after a real name (e.g., Ayu + hime ‘princess’ → Ayu-pime ‘Princess Ayu’). The online sources of these examples were last checked on 2 August 2022; to the best of my knowledge, some of these posts and articles were written as early as 2010.Footnote ³Footnote ⁴Footnote ⁵Footnote ⁶Footnote ⁷Footnote ⁸

This nicknaming pattern, like the examples in (3), is often found in feminine names; thus, it may be induced by the sound-symbolic [h]→[p] alternation. However, pime-yobi nicknaming causes a theoretical issue; the sequence of labial consonants [p…m] in the nickname would violate the constraint that penalises identical place-of-articulation features (here [labial]) occurring in a specific domain, which is a version of the Obligatory Contour Principle (OCP-place; McCarthy Reference McCarthy1986, Reference McCarthy1988). Let us now consider this seemingly challenging issue.

A well-known morphophonological process in Japanese is rendaku, in which a word-initial voiceless consonant /t, k, s, h/ becomes voiced [d, g, z, b] when it is the second member of a compound, as in (5) (Vance Reference Vance1987, Reference Vance and Kubozono2015; Vance & Irwin Reference Vance and Irwin2016). However, the application of rendaku is blocked under several conditions. One of the best-known of these is that, as exemplified in (6), rendaku does not apply when the second member of the compound already contains a voiced obstruent. This restriction is known as Lyman’s Law, and may be formalised as OCP[ $+$ voice, $-$ sonorant] or No-D $^2_{\textrm {m}}$ (Itô & Mester Reference Itô and Mester2003). For example, the second member /tabi/ of the first compound in (6) does not undergo rendaku, because it already contains a voiced [b] before compound formation.

Another condition blocking rendaku is that /h/ does not become [b] when the second member of the compound already contains [m] (Kawahara et al. Reference Kawahara, Ono and Sudo2006; Kawahara Reference Kawahara2015). As shown in (7), for example, the word hime ‘princess’ does not become *bime. Kumagai (Reference Kumagai2017) experimentally examined whether this restriction is attributable to an OCP-labial constraint (i.e., a ban on consecutive labial consonants) observed in other languages (McCarthy Reference McCarthy1988; Selkirk Reference Selkirk1993; Odden Reference Odden1994; Alderete & Frisch Reference Alderete, Frisch and Lacy2007; Coetzee & Pater Reference Coetzee and Pater2008; Zuraw & Yu-An Reference Zuraw and Yu-An2009). The results showed that rendaku is blocked when the second member of the compound would contain consecutive labial consonants *[b…b], *[b…m], *[b…ɸ] after compound formation (except for [b…w]).

Returning to the issue of pime-yobi nicknaming, if the sound-symbolic [h]→[p] alternation causes [hime] to become [pime], this output form contains two labial consonants [p…m], thereby violating OCP-labial. This violation might be regarded as trivial, because sound-symbolic processes often violate constraints enforced in native phonology (Alderete & Kochetov Reference Alderete and Kochetov2017). More importantly, however, the usual [h]→[b] alternation (*[hime]→[bime]) does not appear in pime-yobi nicknaming, even though both [pime] and [bime] equally violate OCP-labial. Therefore, the [hime]→[pime] alternation must be attributed to some other constraint. The current study builds on the analysis of Alderete & Kochetov (Reference Alderete and Kochetov2017) and proposes that pime-yobi nicknaming is induced by a sound-symbolic constraint, Express[p], which is described in detail in §2.4.

2.4 The Express[p] constraint

Alderete & Kochetov (Reference Alderete and Kochetov2017) propose Express constraints as a way to formalise sound-symbolic/iconic aspects of particular sounds in a particular register or lexical stratum. Following this study, Jang (Reference Jang2020) proposed another Express constraint to account for the strategies observed in a baby-talk register, Korean Aegyo, which people use when talking to pets and lovers. The current study proposes a sound-symbolic constraint, Express[p], which requires output forms to have the following phonological features: [labial], and [high-frequency]. The features [labial] and are motivated by the observation that, in children’s phonological development, bilabial stops [p, b, m] are acquired earlier (Jakobson Reference Jakobson1941, Reference Jakobson1968; MacNeilage et al. Reference MacNeilage, Davis and Matyear1997). The feature [high-frequency] is motivated by the frequency code hypothesis, which, as described above, associates smallness with high-frequency sound such as is found in voiceless consonants. Only [p] in Japanese has all three of these phonological features. The Express[p] constraint is defined in §5, where an HG analysis is provided.

As mentioned in §1.2, numerous studies have shown that bilabial consonants can convey the image of cuteness, thereby suggesting that the Japanese language shows sound-symbolic effects of other constraints, such as Express[b], Express[m] or a more general Express[labial]. Although this is an interesting hypothesis to test, an in-depth discussion is beyond the scope of the current study. Therefore, some possibilities are briefly mentioned below. The bilabial nasal [m] (sonorant) may also be associated with the image of cuteness, because sonorants are used more frequently than obstruents in Japanese feminine first names (Shinohara & Kawahara Reference Shinohara and Kawahara2013). However, nasals exhibit a low frequency in the first formant (Reetz & Jongman Reference Reetz and Jongman2009), and are thus less likely to be associated with the image of smallness than [p]. For the same reason, voiced [b] (with low frequency) is also less likely. Moreover, voiced obstruents such as [b] have been reported to evoke an image of ‘dirtiness’ (Kawahara et al. Reference Kawahara, Shinohara and Uchimoto2008; Uno et al. Reference Uno, Shinohara, Hosokawa, Atsumi, Kumagai and Kawahara2020). The more general constraint Express[labial] is discussed in §6.2.

2.5 Motivation for experiments

To summarise, the current study posits that the sound-symbolic [h]→[p] alternation observed in pime-yobi nicknaming is induced by Express[p]. Here, some questions arise regarding pime-yobi nicknaming and Express[p]. One question is whether more [p]s in a nickname produce a further boost to the image of cuteness. This is a key question that must be addressed in HG analysis, where the counting cumulativity effect of the constraint makes a difference in determining the optimal output form (Jäger & Rosenbach Reference Jäger and Rosenbach2006). Numerous studies have addressed the question of whether sound-symbolic effects apply cumulatively (see Kawahara Reference Kawahara2020a; Kawahara & Breiss Reference Kawahara and Breiss2021 for a background overview and analysis). For example, English speakers compared nonce words with one to five ‘large’ phonemes, such as back vowels and voiced consonants (a, u, o, m, l, w, b, d, g). The more large phonemes in a word, the more likely that word was to be associated with a larger size of ‘greeble’, a novel object used for testing (Thompson & Estes Reference Thompson and Estes2011). In Pokémonastics research (Kawahara et al. Reference Kawahara, Noto and Kumagai2018; Shih et al. Reference Shih, Ackerman, Hermalin, Inkelas, Jang, Johnson, Kavitskaya, Kawahara, Oh, Starr and Yu2019 et seq.), the higher the number of moras (two to seven) in a nonce word, the more likely the name was chosen as appropriate for a post-evolved (stronger, heavier, larger) Pokémon character name (Kawahara Reference Kawahara2020c). Other studies have shown that the cumulative sound-symbolic effect is restricted. For example, a name containing two voiced obstruents was more appropriate for post-evolved Pokémon characters than a name with only one voiced obstruent, but no difference in sound-symbolic effect was noted between names with two and three voiced obstruents (Kawahara & Kumagai Reference Kawahara and Kumagai2019b; see also Kawahara & Kumagai Reference Kawahara and Kumagai2019a, Reference Kawahara and Kumagai2021 for the cumulative effect of voiced obstruents in Pokémonastics). The current study addresses the above question in §3 (Experiment 1) by examining whether forms containing one, two or more [p]s are perceived by Japanese speakers as cuter names, and discusses whether Express[p] shows the sound-symbolic effect in a cumulative manner.

Another question focuses on intra- and inter-speaker variation in pime-yobi nicknaming. The sound-symbolic [h]→[p] alternation is optional, and not all speakers perceive pime-yobi nicknames as cute, or even acceptable. Therefore, examining how cute or acceptable pime-yobi nicknaming sounds across different speakers is a crucial task. The current study addresses this question in §4, where Experiment 2 asks Japanese speakers to rate the acceptability and cuteness of three relevant variants regarding pime-yobi nicknaming: hime (the default form of the word meaning ‘princess’), pime (the pime-yobi form) and bime (the rendaku form).

In phonology, variation in output forms has been analysed using various OT approaches: partial constraint reranking (Anttila Reference Anttila, Hinskens, Hout and Wetzels1997; Anttila & Cho Reference Anttila and Cho1998), stochastic OT (Boersma Reference Boersma1998; Boersma & Hayes Reference Boersma and Hayes2001), freely ranked constraints (Reynolds Reference Reynolds1994; Nagy & Reynolds Reference Nagy and Reynolds1997) and ranking candidates (Coetzee Reference Coetzee2006). In HG models, variation is captured using stochastic versions of HG, such as MaxEnt HG and Noisy HG (for Noisy HG, see Boersma & Pater Reference Boersma, Pater, McCarthy and Pater2016; Hayes Reference Hayes, Jesney, O’Hara, Smith and Walker2017; Zuraw & Hayes Reference Zuraw and Hayes2017; Flemming Reference Flemming2021). The current study adopts MaxEnt HG to model the variants of pime-yobi nicknaming, based on the results of Experiments 1 and 2, thereby establishing that the weight of Express[p] varies across particular speakers and between two distinct phonologies – expressive and non-expressive phonology (see §5).

3.1 Task and stimuli

To examine whether Express[p] displays a cumulative sound-symbolic effect, Experiment 1 tested whether the number of singleton [p]s in names affects the image of cuteness. The experiment used a two-alternative forced-choice task, wherein participants were given two nonce words and asked to select the name they felt was cuter. As shown in Table 1, three conditions compared names with one or more [p]s (target stimuli in the right columns) and those without any [p]s; each form consisted of three CV moras. The first condition contained singleton [p] in the first mora; the second condition contained two singleton [p]s in the first and second moras and the third condition contained three singleton [p]s. The other consonants used besides [p] were [ç, ɸ, h], the allophones of /h/ before [i], [u] and [a, e, o], respectively (e.g., Vance Reference Vance1987; Labrune Reference Labrune2012; Tsujimura Reference Tsujimura2013). Each condition comprised 10 pairs. A total of 30 pairs were presented.

Table 1 Stimuli used in Experiment 1.

3.2 Procedure

The current experiment was implemented online using the ‘buy response’ function provided by SurveyMonkey, in which participants are given a monetary reward after completing the experiment. Participants were first given a consent form to sign if they agreed to participate and then asked whether they were native Japanese speakers and if they had ever heard of the term ‘sound symbolism’. Only those who were native Japanese speakers and had never heard of the term ‘sound symbolism’ were allowed to participate.

The current experiment used orthographic stimuli using katakana characters, the orthography usually used to represent loanwords in Japanese. The participants were instructed to select which of the two names sounded cuter (kawaii in Japanese). They were not provided with a definition of cuteness or kawaii. They were given one practice question, which asked which of the two names ramire and remire sounded cuter, before answering 30 questions. The orders of two names within each pair and 30 pairs of stimuli were randomised for each participant. After completing all the questions, participants were asked about their age and gender.

3.3 Participants

The participants were 100 native Japanese speakers, of whom 64 were women and 36 were men. Most participants ( $n=96$ ) were aged between 20 and 39 years (47 speakers between 20 and 29; 49 speakers between 30 and 39). Three were over 50 years old, and one was between 18 and 19 years old.

3.4 Statistics

The two-alternative forced-choice task provided a categorical response; thus, a logistic regression model (Winter Reference Winter2019) was fitted to the experimental results, using the glmer function in the lme4 package (Bates et al. Reference Bates, Maechler, Bolker, Walker, Christensen, Singmann, Dai and Grothendieck2015) in R (R Core Team 2020). As a response variable, the response for which the target stimulus was judged to be a cute name was coded as 1, and the no-[p] response was coded as 0. The model included a fixed-effect predictor called Condition, which is the number of [p]s in the items containing at least one [p], ranging from one to three. The model also included by-stimulus random intercepts and by-participant random intercepts, as well as by-participant random slope adjustments to Condition (Baayen et al. Reference Baayen, Davidson and Bates2008). The data files for analysis are available at https://osf.io/pj5qz/.

4.1 Task and stimuli

Experiment 2 examined how Japanese speakers rated acceptability and cuteness for three variants relevant to pime-yobi nicknaming: nicknames with hime (the default form meaning ‘princess’), pime (the pime-yobi form) and bime (the unattested form that would result from rendaku). The stimuli used are listed in Table 3.

Table 3 The set of stimuli in Experiment 2.

Participants were provided non-real bimoraic names, and for each name N, they were asked to compare ‘N-pime’ with ‘N-hime’ (Condition 1) and ‘N-bime’ with ‘N-hime’ (Condition 2), using the rating scales in (8). For each criterion, a score of 3 is the baseline, indicating that the two nicknames sound equally acceptable or equally cute. For instance, if a participant believed that yaka-pime sounded as acceptable as yaka-hime in the first pair of Condition 1, they assigned a score of three points. Each condition comprised seven pairs, and a total of 14 pairs were presented.

4.2 Procedure

As in the previous experiment, Experiment 2 recruited participants using the ‘buy response’ function in SurveyMonkey and obtained their consent through a consent form. Participants were asked whether they were native Japanese speakers, and if they had ever heard of the terms ‘sound symbolism’ and ‘rendaku’. All participants were native Japanese speakers, and no participant reported that they had ever heard of the terms ‘sound symbolism’ and ‘rendaku’.

Experiment 2, like Experiment 1, used katakana characters as the orthographic stimuli. Participants were presented with feminine nicknames suffixed with hime, pime and bime, and were then requested to rate the acceptability and cuteness of each pair using the scales in (8). In the judgement tasks, the Japanese words sizen ‘natural’ and kawaii ‘cute’ were used to refer to the relevant properties (e.g., X wa Y yorimo sizen-da = ‘X sounds more acceptable than Y’; X wa Y yorimo kawaii = ‘X sounds cuter than Y’). As in Experiment 1, the current experiment did not define ‘cute’ or kawaii. After practising how to assign scores, the participants first evaluated acceptability for all 14 pairs and then evaluated the cuteness of all these pairs. All pairs and names within each pair were presented to each participant in random order. After completing the task, participants were asked about their age and gender.

4.3 Participants and grouping for analysis

Experiment 2 recruited 100 native Japanese speakers who were different from those in Experiment 1. They were categorised, based on their average scores in Condition 1 (pime vs. hime) in the cuteness judgement task, into three subgroups. Those whose average score was greater than three points – meaning that they judged pime as cuter than hime – were categorised as ‘cuteness-sensitive speakers’ ( $n=34$ ). In contrast, those who scored less than three points on average for the same condition – that is, those who judged hime to be cuter than pime – were categorised as ‘cuteness-insensitive speakers’ ( $n=50$ ). The remaining 16 participants, who had a mean rating of exactly 3.0, were categorised as ‘other’ and not analysed further. Table 4 shows the demographic composition of each group.Footnote ⁹

Table 4 Numbers of participants in each category in Experiment 2 by age and gender.

Categorising cuteness sensitivity by age and gender may yield interesting results. This analysis is, however, left for Appendix A, because the current results do not show that these two factors were associated with any significant differences in cuteness sensitivity.

4.4 Statistics

A linear mixed-effects model was fitted to the experimental results using the lmer function in the lme4 package (Bates et al. Reference Bates, Maechler, Bolker, Walker, Christensen, Singmann, Dai and Grothendieck2015) in R (R Core Team 2020). The response variable was the score (1 at the minimum and 5 at the maximum). Similar to the analysis in Experiment 1, the model included by-stimulus random intercepts and by-participant random intercepts, as well as by-participant random slope (Baayen et al. Reference Baayen, Davidson and Bates2008). The lmer function does not produce p-values (Baayen et al. Reference Baayen, Davidson and Bates2008); thus, p-values were calculated after installing the lmerTest package (Kuznetsova et al. Reference Kuznetsova, Brockhoff and Christensen2017). The data files for analysis are available at https://osf.io/pj5qz/.

4.6 Discussion: The order of acceptability and cuteness

Based on the experiment results, the current section discusses the order of acceptability and cuteness of the three variants for cuteness-sensitive and cuteness-insensitive speakers. For cuteness-sensitive speakers, the average scores in the [p] and [b] conditions (2.89 for [p]; 2.62 for [b]) were less than 3.0 (the baseline) in the acceptability judgement task, although the score in the [p] condition was significantly higher than that in the [b] condition. Therefore, the order of acceptability is hime $>$ pime $>$ bime. However, in the cuteness judgement task for these speakers, the average score in the [p] condition (3.93) was above the baseline, and the average score in the [b] condition (2.77) was below it, with the difference being significant. Therefore, the order of cuteness is pime $>$ hime $>$ bime.

For cuteness-insensitive speakers, the average scores in the [p] and [b] conditions were less than 3.0 in both the acceptability and cuteness judgement tasks, and no difference was noted between the two labial stops in either acceptability or cuteness. Therefore, both the acceptability and cuteness order are hime $>$ pime = bime. The order of acceptability and cuteness discussed here is summarised in Table 6, where ‘A $>$ B’ means that A sounds more acceptable/cuter than B and ‘A = B’ means that A sounds as acceptable/cute as B. Whether each order of acceptability and cuteness can be predicted based on the H-score of each candidate is examined in §5.5.

Table 6 Relative acceptability and cuteness of forms as judged by cuteness-sensitive and -insensitive speakers.

5.1 A brief explanation of MaxEnt HG

MaxEnt HG (Goldwater & Johnson Reference Goldwater, Johnson, Spenader, Eriksson and Dahl2003; Jäger Reference Jäger, Zaenen, Simpson, King, Grimshaw, Maling and Manning2007; Hayes & Wilson Reference Hayes and Wilson2008) is a probabilistic model based on HG (Legendre et al. Reference Legendre, Miyata, Smolensky and Ringle1990, Reference Legendre, Sorace, Smolensky, Smolensky and Legendre2006; Pater Reference Pater2009, Reference Pater, McCarthy and Pater2016; Potts et al. Reference Potts, Pater, Jesney, Bhatt and Becker2010). In standard HG, the harmonic score (H-score) is calculated for each candidate based on the sum of $C_i \times w_i$ , where for each constraint i, the number of violations of i incurred by the candidate ( $C_i$ ) is multiplied by the weight of the constraint ( $w_i$ ). The candidate with the lowest H-score is selected as the winner. Rather than merely selecting an individual winner, MaxEnt HG uses the H-scores to calculate predicted probabilities for all output forms, including harmonically bounded candidates (Jäger & Rosenbach Reference Jäger and Rosenbach2006). The procedure is as follows. First, each candidate’s eHarmony is calculated as $e^{-\textrm {H-score}}$ , where e is the base of natural logarithms. Second, Z is calculated by summing eHarmony for all candidates. Finally, the predicted probability of each candidate is eHarmony divided by Z.

The MaxEnt calculation is illustrated in (9), which shows two candidates being evaluated by three constraints weighted as follows: , and . Candidate 1 incurs two violations of Con1 and one violation of Con2, and Candidate 2 incurs one violation of Con3. In this case, the H-score of Candidate 1 is 4 (), giving it an eHarmony of 0.0183 ( $= e^{-4}$ ), and the H-score of Candidate 2 is 3 (), for an eHarmony of 0.0498 ( $= e^{-3}$ ). Z is the sum of the two eHarmony values ( $0.0183 + 0.0498 = 0.0681$ ). Consequently, the predicted probability of Candidate 1 is 0.2689 ( $= 0.0183/0.0681$ ), and the predicted probability of Candidate 2 is 0.7311 ( $= 0.0498/0.0681$ ).

The current MaxEnt HG analysis is based on the results of Experiments 1 and 2. Experiment 1 showed that Japanese speakers found names with [p]s to be cuter than those without them, which suggests a categorical [p]-favouring constraint that prefers candidates with at least one [p], but does not motivate multiple [p]s. Experiment 2 showed that acceptability and cuteness judgements of the variants in pime-yobi nicknaming are gradient across different speakers, and that the variant bime, though unattested in observed usage, is selected by some speakers.

5.2 Constraints

The four constraints needed for the current analysis are defined in (10).

The current analysis posits that the Express[p] constraint in (10a) distinguishes candidates with [p]s from those without any [p]s, based on the results of Experiment 1. For example, the output form pime contains one singleton [p], and thus incurs no violation marks; the forms hime and bime contain no [p], incurring one violation mark each.

The Realise Morpheme (Kurisu Reference Kurisu2001) and Ident[F] (McCarthy & Prince Reference McCarthy and Prince1995, Reference McCarthy, Prince, Kager, van der Hulst and Zonneveld1999: 226) constraints in (10b) and (10c) are used in Itô & Mester’s (Reference Itô and Mester2003) analysis of rendaku, in which Realise Morpheme takes precedence over Ident[F] (i.e., ).Footnote ¹⁰ Itô & Mester (Reference Itô and Mester2003) posit a featural linking morpheme ℜ specified with [+voice]; in their analysis of rendaku, RealMorph is satisfied if this feature is realised on some segment in the output (e.g., hako ‘box’ + ℜ + hune ‘ship’ → hako-bune ‘ark’). However, the current study assumes that it treats both [p] and [b] as phonological exponents of compoundhood, since we are concerned here not only with the rendaku form and its voicing alternation (hime→bime) but also with the nickname and its [h]→[p] alternation (hime→pime). In other words, not only nicknames with bime (the rendaku form), but also those with pime (the pime-yobi form) satisfy RealMorph.Footnote ¹¹

One might suspect that Exp[p] and RealMorph functionally overlap with each other, as both motivate the [h]→[p] alternation in pime-yobi nicknaming. However, the two constraints are distinguished from each other. As mentioned in §2.3, we observe the [h]→[p] alternation in ambient language data, but not [h]→[b]. Thus, there should be a constraint (Express[p]) that specifically favours [p] and is distinct from Realise Morpheme, which is equally well satisfied by either pime or bime.

The current analysis also posits the OCP(Lab) constraint in (10d), confirmed in a nonce-word experiment (Kumagai Reference Kumagai2017, Reference Kumagai2019). There are monomorphemic native words with two labial consonants in Japanese, such as mame ‘bean’, mimi ‘ear’ and momo ‘peach’. Thus, Ident must be assigned a substantially higher weight than OCP(Lab) ().

We see the constraint violation profile of rendaku blocking in (11). As explained above, the relative weighting of the constraints is . As seen in §2.3, hime ‘princess’ does not undergo rendaku to become *bime (e.g., mai-hime ‘dancing girl’; *mai-bime), and Experiment 2 confirmed that hime is more acceptable than bime (see Table 6). The form hime is chosen as a winner, even though it violates the highest-weighted of these three constraints, RealMorph. This is an instance of ganging-up cumulativity: violations of multiple lower-weighted constraints collectively outweigh a violation of a higher-weighted constraint (Jäger & Rosenbach Reference Jäger and Rosenbach2006). In the hime→*bime case, the lower-weighted constraints Ident and OCP(Lab) together overcome RealMorph.

We then see the constraint violation profile of pime-yobi nicknaming in (12). Experiment 2 showed that pime was judged as a cuter name than hime by cuteness-sensitive speakers (see Table 6). This effect is due to Express[p]; as shown in (12), hime (without [p]) incurs one violation mark and is thereby evaluated as less cute than pime (by some speakers). In addition, bime is harmonically bounded by pime, which can explain the fact that the hime→*bime case is not observed in real nicknames.

5.3 Cuteness-expressive phonology

The current HG analysis captures the gradient acceptability of the pime-yobi variants by building on the concept of co-phonology, namely, multiple strata or subgrammars within a language (Itô & Mester Reference Itô, Mester and Goldsmith1995; Orgun Reference Orgun1996; Inkelas Reference Inkelas, Booij and Marle1998; Itô & Mester Reference Itô, Mester and Tsujimura1999; Anttila Reference Anttila2002; etc.). Two types of co-phonology in Japanese speakers are assumed here: non-expressive phonology, defined as the grammar used for acceptability judgement, and I-expressive phonology, defined as the grammar used for judgement of an image I. The current study assumes that the cuteness-expressive phonology used for cuteness judgement is an I-expressive phonology.Footnote ¹²

5.4 Input data

The current analysis calculates constraint weights using the Maxent Grammar Tool software (Hayes Reference Hayes2009). This calculation requires input data for learning. (The input data files are available at https://osf.io/pj5qz/.) The input values for the calculation are shown in (13) and (14). (13a) and (13b) correspond to Conditions 1 and 2 of Experiment 2, respectively. The input–output pairs in (13a) compare two output forms hime and pime for the input form hime, and the input–output pairs in (13b) compare two output forms hime and bime for the same input form. The shaded region indicates the constraint violation profiles for the candidates. The last four columns show the frequencies reported in Table 5, which were used to calculate the constraint weights for each co-phonology: ns = non-expressive phonology in cuteness-sensitive speakers; es = expressive phonology in cuteness-sensitive speakers; ni = non-expressive phonology in cuteness-insensitive speakers; and ei = expressive phonology in cuteness-insensitive speakers. In terms of the constraint violation profile, the candidate bime is harmonically bounded by pime (i.e., no possible weighting of constraints will prefer bime over pime, because bime’s constraint violations are a proper superset of pime’s), but MaxEnt HG allows us to calculate a (non-zero) probability for every candidate, including harmonically bounded ones (Jäger & Rosenbach Reference Jäger and Rosenbach2006).

The input values in (14) were used to ensure that in Japanese phonology. In (14a) candidate mame ‘bean’ is faithfully selected as a winner, even though it violates OCP(Labial). In (14b), rendaku produces hune→bune ‘ship’, since RealMorph is substantially more heavily weighted than Ident. The preference for the winning candidate in each pair was assumed to be categorical – that is, 1 vs. 0 for both mame over name and bune over hune.

6.1 Summary

The current study is briefly summarised in this section. Pime-yobi is a new Japanese nicknaming pattern that uses an [h]→[p] alternation to express cuteness. The current study proposes that this pattern is induced by a constraint Express[p], which requires output forms to contain a singleton [p]. The two experiments conducted have shown that names with [p]s are found to be cuter than those without them, and the degrees of acceptability and cuteness for the variants of the pime-yobi nicknaming are different across speakers. Based on the experimental results, the current study modelled pime-yobi nicknaming patterns using MaxEnt HG, in which we saw that the sound-symbolic effect of Express[p] is gradient across different speakers (cuteness-sensitive vs. cuteness-insensitive) and within two types of co-phonology (non-expressive vs. cuteness-expressive), and in addition, a variant bime, though harmonically bounded by pime, is assigned non-zero probability.

6.2 Questions for future research

Is Express[p] active in languages other than Japanese? The current study has noted (§1.2) that Express[p] is rooted in cross-linguistic patterns in phonological development and the frequency-code hypothesis, which associate cuteness with labiality and high frequency. Therefore, the sound-symbolic effect in question should be found in other languages that have [p] or some other sound that has these properties. Recent experimental studies have shown that labial consonants (including [p]) are more likely to be associated with an image of cuteness than non-bilabial consonants across several languages (Kumagai Reference Kumagai2020; Kawahara et al. Reference Kawahara, Godoy and Kumagai2021; Kumagai & Moon Reference Kumagai and Moon2021). Further research is needed to examine whether the sound-symbolic association of labials with cuteness, or a more generalised constraint, Express[labial], is cross-linguistically ubiquitous.

As noted by Alderete & Kochetov (Reference Alderete and Kochetov2017) (see §1.1), sound-symbolic effects have yet to be actively discussed in the literature on theoretical phonology. However, recent studies have shown that sound-symbolic phenomena can be modelled using theoretical tools such as MaxEnt HG (Kawahara et al. Reference Kawahara, Katsuda and Kumagai2019; Jang Reference Jang2020; Kawahara Reference Kawahara2020c,Reference Kawaharaa, Kawahara Reference Kawahara2021; Shih Reference Shih, Baek, Takahashi and Yeung2020). The current study contributes to this discussion by proposing a sound-symbolic Express constraint and modelling a Japanese nicknaming pattern, pime-yobi, in MaxEnt HG.