Published online by Cambridge University Press: 18 February 2010
In chapter 4, we have seen that speakers manipulate their phonetic implementation for communicative purposes in a way that is to some extent independent of the language they speak. In this chapter, it is argued that the knowledge people have of these form–function relations derives from three biologically determined conditions. One is that the organs with which we produce speech, in particular the larynx, vary in size, the second that the production of speech requires energy and that variation in effort is detectable in the signal, and the third is that the supply of this energy occurs in phases, as determined by the breathing process. The exploitation of the connection between F0 and size of the organism, with smaller larynxes producing higher notes than larger ones, was identified as the Frequency Code by Ohala (1983). Variation in effort is associated with the excursion size of pitch movements, greater effort leading to wider excursions, the Effort Code (Gussenhoven 1999c). Third, the Production Code associates high initial pitch with beginnings and final low pitch with endings of speech events (Gussenhoven 2002).
Before moving on, it must be stressed that speakers do indeed actively control their phonetic implementation, for a variety of purposes. Phonetic implementation is not automatic, such that given the physiological properties of the speaker, the acoustic realization of a linguistic representation is given (Kingston and Diehl 1994). To put the discussion in its right perspective, section 5.2 considers phonetic variation which is not under speaker control, while section 5.3 deals with a variety of non-intonational purposes for control in phonetic implementation.