Speakers, Listeners, Languages: Patterns Of Variability And Contrast In Spoken Language Dynamics

The goal of our proposed project is to shed new light on how the basic dynamics of speech production and perception are shaped by language-specific linguistic structure and may, at the same time, vary between individuals of the same language community in a systematic fashion.

A defining characteristic of human spoken language is the dynamic, interwoven production of individual meaningful speech units (phonemes) which together form words and sentences.

Although we may represent phonemes orthographically as sequences of letters, the realization of phonemes in speech production does not unfold in time like beads on a string.

Rather, the way that we produce these individual speech sounds is affected by and dependent upon the sounds that precede and follow them in time, a phenomenon known as coarticulation.

Coarticulation ensures rapid and effective communication - it is actively planned and is part of learned, language-specific speaker knowledge.

Also in perception, listeners actively seek out the dynamic cues of coarticulation in a speaker's production when determining which words were spoken.

While it has repeatedly been argued that phonological contrast - i.e., which sounds form part of a language's inventory - constrains the degree of coarticulation, the empirical evidence for this claim has remained ambiguous, since variation between languages does not necessarily pattern as predicted by phonological structure.

At the same time, there is substantial variation in coarticulatory patterns among individual speakers of the same language.

Recent studies have uncovered that this individual variation in how phonological contrast is signaled may be not just 'noise' but instead part of a high-dimensional, language-specific production-perception dynamic which is currently little understood.

The proposed project will enable us obtain a comprehensive view on the relation between perceived and produced speech for individual language users, at a scale that will allow us to assess levels of structured variability among individuals both within and between languages.

Our work will focus on two phonological contrasts (nasality and lip rounding), in three languages (English, German, French), and include a larger number of participants than most previous studies.

The project's unprecedented scope has therefore the potential to open new perspectives on 1) why and how languages differ from each other, 2) what aspects of language variation are universal to all human language users, 3) how sound systems evolve, and 4) the cognitive relationship between speech production and perception.

The further benefit of the project lies in making available to the scientific community a comprehensive cross-linguistic database that can be used for research and teaching purposes.