Connected speech in Romanian: Exploring sound change through an ASR system

This study explores the hypothesis that traces of sound change can be found in connected speech processes as synchronic variation. To test this hypothesis we study the variation in connected speech through the output of an ASR system (Adda-Decker and Lamel, 1999). The case study is the vowel alternation [e]–[ʌ] after labials, encountered in Romanian historically, as part of a relatively sporadic sound change with unclear conditioning, as well as synchronically, as a phenomenon commonly observed in continuous speech. The specific question we address is whether the synchronic phenomenon in Romanian continuous speech is simply the result of general vowel reduction, or may reflect the sound change, with its apparent sensitivity to a labial consonantal context. We focus on the prepositions [pe] ‘on’ and [de] ‘of’, chosen specifically for their status as function words, more prone to vowel reduction than lexical words. We compare the ASR system’s choice of two transcription variants and their respective contexts. The results of this comparison suggest that the synchronic variation is grounded in the historical sound change, thus motivating a future systematic study of controlled speech, to determine the exact role of segmental contextual factors. The main result is that the selection of transcription variants is significantly different for the two prepositions. This allows us to better understand the conditioning environment of the relevant sound change, and reveals the language-specific articulatory and co-articulatory settings and dynamic patterns that may have led to it, as they emerge and can be observed in continuous speech.