Phonetic Accommodation in Non-native Directed Speech Supports L2 Word Learning and Pronunciation.

This study assessed whether Non-native Directed Speech (NNDS) facilitates second language (L2) learning, specifically L2 word learning and production. Spanish participants (N=50) learned novel English words, presented either in NNDS or Native-Directed Speech (NDS), in two tasks: Recognition and Production. Recognition involved matching novel objects to their labels produced in NNDS or NDS. Production required participants to pronounce these objects’ labels. The novel words contained English vowel contrasts, which approximated Spanish vowel categories more (/ɪ-i/) or less (/æ-ɛ/). Participants assigned to the NNDS group recognized novel words faster and learned and pronounced the /ɪ-i/ contrast words better compared to participants in the NDS group. Participants’ ability to discriminate the target vowel contrasts was also assessed before and after the tasks, with no improvement detected in the two groups. These findings support the didactic assumption of NNDS, indicating the relevance of the phonetic adaptations in this register for successful L2 acquisition.