Range of variability in native and non-native spontaneous speech intervocalic stops

Abstract

Speakers produce sounds differently in spontaneous vs careful speech, and how they do this shows both similarities and differences across languages. The current project examines spontaneous conversational speech and read speech among monolingual English speakers, Dutch-English bilinguals, and Spanish-English bilinguals (for Dutch and Spanish, in both their L1 and English). The phonology of intervocalic stops differs in these languages: Dutch has final devoicing, Spanish has approximation of /bdg/, and English has flapping of /td/. In our recordings, Dutch speakers often devoiced final stops in both Dutch and English in spontaneous speech, while native English speakers produced voiced stops or approximants. Speakers of all the languages produced some approximant realizations and some deletions. Through measurements of consonant duration, amplitude dip during the consonant, and cessation of voicing, this work shows the range of acoustic variability produced by speakers of three languages in their L1 and their L2, in spontaneous and careful speech. This allows a comparison of how much of speech variability stems from the native language phonology, from language-specific phonetics, and from language-general spontaneous speech reduction.