It has long been known that HLuvian sign 383, an oblique stroke (\), when added to another sign, indicates the presence of a postvocalic r: see the references cited by Laroche, HH 205. The “thorn”, as it is often called, may indicate /r/ alone, or a sequence /ra/ or /ri/. The now standard transliteration ra/i is thus a cover symbol for all three possibilities. The actual reading in any particular case may be determined only on comparative grounds, internal or external. As examples of /r/, /ra/, and /ri/1 may cite respectively dat.-loc. pl. (“FINES”)I + ra/i-ha-za = /irhanza/ “boundaries” (cf. Hitt. irḫa- “idem”), pret. 3rd sg. i + ra/i = /ira/ “went”, and pres. 3rd sg. i + ra/i = /iri/ “goes”.
Hawkins, Morpurgo-Davies and Neumann, HHL 171 f, have argued that in internal and final position the combination 209 + 383 (), in addition to i + ra/i, may also indicate ri+i = /ri/. That is, in combination with a vowel sign V, the “thorn” may indicate the sequence /rV/ instead of/Vra/i/. Note that the HLuvian syllabary has no CV sign for /ri/, while sign 412 (and less often sign 103) spells /ru/. Evidence for the reading ri+i comes from alternations such as abl./inst. DEUS-na-ri+i beside deus-na-ti-(i) “by/from the god(s)” or tu-pi-ri+i beside tu-pi-ti-i “strikes”.