Overt and covert contrast in L2 phonology.

This paper reports results on the acquisition of the English /p/ - /b/ contrast by native speakers of Arabic. This contrast does not exist in the participants' native language (NL). The central finding of this study is that some of the research participants exhibited a covert contrast between these segments in their interlanguage productions. That is, two of the five Arabic-speaking participants who were transcribed as having no contrast between [p] and [b] did, in fact, produced a statistically reliable distinction in voice onset time lags between the two target segments. The existence of such an intermediate stage of covert contrast in the learning of L2 phonology is eminently plausible, in view of the progressive nature of phonological acquisition. Our results help bring the learning of second-language contrasts into conformity with findings of the same phenomenon in the areas of L1 acquisition and phonologically disordered speech.