Articulation of the Japanese Moraic Nasal: Place of Articulation, Assimilation, and L2 Transfer

The moraic nasal /N/ in Japanese has been transcribed in multiple ways, but very few studies have examined its articulation. The nature of its assimilation has often been described in phonology, but again, very few articulatory investigations have been conducted. Also, while a first language (L1) effect on second language (L2) production has been discussed for some phonemes, there is no good research on the effect of Japanese /N/ on L2 English syllable-final nasals. This dissertation investigates the articulation of the moraic nasal /N/ in Japanese using an ultrasound articulatory imaging technique to assess 1) its place of articulation, 2) patterns of place assimilation to the following segment, and 3) the effect of L1 /N/ on L2 English syllable-final nasal production. Eight native speakers of Japanese participated. Their productions of Japanese words and English words were analyzed acoustically and articulatorily. The results showed that the place of articulation for utterance-final /N/ following the vowel /a/ varied across native speakers of Japanese from alveolar to uvular, which is compatible with previous descriptions of /N/ in intervocalic position. Patterns of place assimilation of the moraic nasal to a following segment were not always categorical, and a gesture for the target of the moraic nasal, while varying among individuals, sometimes remained depending on the phonological environments. This suggests that the assimilation takes place not only at the phonological level but also at the phonetic level, even if the assimilation is considered to be obligatory. An effect of L1 /N/ on the production of word-final nasals in L2 English was observed, although the degree of the effect varied across speakers. In conclusion, these findings enhance our understanding of the articulatory characteristics of the moraic nasal /N/ in Japanese, providing a firmer basis for phonological and phonetic arguments. The findings should also encourage further investigation and discussion of the phonological and phonetic behavior of /N/