Research attempting to understand the intermediate stages of first-language acquisition and disordered speech has led to the discovery of covert contrast. A covert contrast is a statistically reliable difference between phonemes that is produced by a language learner, but in a way that cannot be heard readily by a listener of the target language.…

We present findings of an investigation into the acquisition of the English /s/-/esh/ contrast by native speakers of Korean and Japanese. Both of these languages have the phones [s] and [esh], and both languages exhibit a pattern--or motivate a rule--whereby /s/ is realized as [esh] before the vowel [i] and the glide [j]--that is, high front…