Japanese adults can learn to produce English /r/ and /l/ accurately.

As is well known, Japanese adults who have just begun to learn English often err in producing /r/ and /l/ because their native language does not possess such liquid consonants. The aim of this study was to determine if Japanese adults eventually learn to produce /r/ and /l/ accurately in words like read and lead. Liquids spoken by 12 native Japanese speakers who had lived in the United States for an average of two years were often misidentified by native English-speaking listeners. Their productions of /r/ and /l/ also received much lower (and thus foreign-accented) ratings than did the native English speakers' liquids. On the other hand, liquids produced by native Japanese speakers who had lived in the United States for an average 21 years were identified correctly in forced-choice tests. This held true for liquids in words that had been read from a list as well as for words that had been spoken spontaneously. The ratings of liquids produced by 10 of the 12 experienced Japanese speakers fell within the range of ratings obtained for the 12 native English speakers. These findings challenge the widely accepted view that segmental production errors in a second language arise from the inevitable loss of ability to learn phonetic segments not found in the native language.