This paper describes on-glide nasal [d] and [g] at initial and medial positions in Shikoku dialects. Acoustic analysis was used to examine on-glide nasal [g] at initial position in Kochi, Tokushima and Kagawa dialects and it was found that this phone occurs in Kochi dialects but not in Tokushima and Kagawa dialects. Language geographical analysis showed that on-glide nasal [d] and [g] at medial position occur in Tokushima dialect, but have almost disappeared except in isolated areas. Analysis also showed that, in Tokushima dialect, on-glide nasal [g] at medial position tends to disappear faster than on-glide nasal [d].
