The developmental trajectory of children's perception and production of English /r/-/l/.

The English /l-r/ distinction is difficult to learn for some second language learners as well as for native-speaking children. This study examines the use of the second (F2) and third (F3) formants in the production and perception of /l/ and /r/ sounds in 4-, 4.5-, 5.5-, and 8.5-yr-old English-speaking children. The children were tested with elicitation and repetition tasks as well as word recognition tasks. The results indicate that whereas young children's /l/ and /r/ in both production and perception show fairly high accuracy and were well defined along the primary acoustic parameter that differentiates them, F3 frequency, these children were still developing in regard to the integration of the secondary cue, F2 frequency. The pattern of development is consistent with the distribution of these features in the ambient input relative to the /l/ and /r/ category distinction: F3 is robust and reliable, whereas F2 is less reliable in distinguishing /l/ and /r/. With delayed development of F2, cue weighting of F3 and F2 for the English /l-r/ categorization seems to continue to develop beyond 8 or 9 yr of age. These data are consistent with a rather long trajectory of phonetic development whereby native categories are refined and tuned well into childhood.