An Acoustic Model of Communicative Efficiency in Consonants and Vowels Taking into Account Context Distinctiveness

Speaking is generally considered efficient in that less effort is spent articulating more redundant items. With efficient speech production, less reduction is expected in the pronunciation of phonemes that are more important (distinctive) for word identification. The importance of a single phoneme in word recognition can be quantified as the information (in bits) it adds to the preceding word onset to narrow down the context corrected lexical search. In our study, segmental information showed to correlate consistently with both duration and spectral reduction in vowels and most consonants. No such correlations were found for stops and only little for nasals. This correlation was found after accounting for speaker and vowel identity, speaking style, lexical stress, modeled prominence, position in the syllable, and position of the phoneme in the word. We conclude that speech is organized for efficiency at the level of the phoneme.