Читать книгу The Concise Encyclopedia of Applied Linguistics - Carol A. Chapelle - Страница 226

Flege and his collaborators have shown a phonological accent, in both L1 and L2, when bilinguals produce speech sounds (e.g., Flege, 2002). In some studies they measured the “voice onset time” (VOT) of consonants spoken by bilinguals and monolinguals in the context of a larger language fragment. The VOT is the time between the release of the air and the moment the vocal cords start to vibrate when a speaker produces a consonant. The VOT for one and the same consonant may differ between languages. For instance, the consonant /t/ is spoken with a longer VOT in English than in French and Spanish. This fact gives rise to the question of how bilingual speakers of two languages that exploit different VOT values in producing one and the same consonant utter this consonant. Flege and his colleagues have shown that the VOT values of such consonants differ between monolinguals and bilinguals. Specifically, when spoken by bilinguals these consonants take on VOT values that are intermediate between those of the same consonants spoken by monolingual speakers of the two languages concerned. For instance, if English–French bilinguals and English monolinguals are asked to pronounce the speech fragment two little dogs, the VOT of the /t/ sound in two is shorter for the English–French bilinguals than for the English monolinguals. Conversely, if English–French bilinguals and French monolinguals are asked to pronounce the speech fragment tous les chiens, ‘all dogs’, the VOT of the /t/ sound in tous is longer for the English–French bilinguals than for the French monolinguals.

Flege (2002) attributed these phonological accents to two L2 speech learning processes. One of these, “phonetic category assimilation,” is thought to lead to representations that merge closely similar L1 and L2 sounds into a single phonetic category in memory. The second, “phonetic category dissimilation,” is thought to operate when an L2 sound is very different from all L1 sounds stored in memory. A separate representation for the new L2 sound is then formed in memory, but the position it takes up in phonetic space differs from the position occupied by this sound in monolingual speakers of the language concerned. Furthermore, while inserting a phonetic category for this new sound into the phonetic space, it pushes away one or more of the categories that represent L1 sounds from their original positions (causing an accent).

Though category assimilation and dissimilation provide a plausible explanation of the phonological accents in bilingual speech production, an account in terms of parallel activation of two analogous L1/L2 phonetic categories (e.g., a French‐like /t/ and an English‐like /t/) appears equally plausible, at least for both early bilinguals and late proficient bilinguals. Early bilinguals can already perceive the difference between certain pairs of closely similar L1 and L2 phonetic categories from 10 to 11 months onward (e.g., Sundara, Polka, & Molnar, 2008) and late proficient bilinguals can also do this (Flege, 2007). This discrimination ability clearly points toward the existence of separate phonetic representations for similar L1/L2 sounds because it is hard to see how a difference between two such speech sounds can be perceived at all if they share one and the same representation. The very existence of such pairs of representations for speech sounds that are similar in L1 and L2 renders an interpretation of accented speech sounds in terms of their parallel activation plausible (see De Groot, 2014).