There is a long-standing debate in the literature about the benefits that acoustic components of Infant Directed Speech (IDS) might have for infants' language acquisition. One of the highly contested features is vowel space expansion, which refers to the enlargement of the acoustic space between the corner vowels /i, u, a/ in IDS compared to Adult…

Hyper-articulation of vowel and consonant contrasts is often reported in infant-directed speech (IDS), but is not universal cross-linguistically, and may be a side-effect of speaking rate. This study investigated the voicing characteristics of the four-way oral stop voicing contrast in Nepali IDS. Both lead and lag time of word-onset/g,…

Previous research has shown that an increased second language (L2) vocabulary size leads to better attunement to the cues required to distinguish L2 contrastive phones. This has been the central tenet of the vocabulary-tuning model (vocab) on the basis of evidence by Japanese learners of English in Australia. We aim to test the validity of the…