English: In green region (1), four kana "じ", "ず", "ぢ", and "づ" are homophonic. In yellow region (2), "じ" and "ぢ" are homophonic, and also "ず" and "づ" are homophonic. But "じ" and "ず", "ぢ" and "づ" are pronounced differently. In orange region (3), "じ" and "ぢ" are homophonic, but each of "ぢ", "ず", "づ" has different pronunciation. In purple region (4), each of "じ", "ぢ", "ず", "づ" has different pronunciation.
Reference
大野晋、柴田武編 『岩波講座 日本語11 方言』 岩波書店、1977年、255-256頁。ŌNO Susumu, SHIBATA Takeshi ed. Iwanami Kōza Nihongo 11 Hōgen (Iwanami Japanese Language Course Vol. 11 Dialects), Tokyo: Iwanami Shoten, 1977, pp. 255 f.
平山輝男編 『現代日本語方言大辞典 第1巻』 明治書院、1992年、図11、33頁。HIRAYAMA Teruo ed. Gendai Nihongo Hōgen Daijiten 1 (Comprehensive Dictionary of Modern Japanese Dialects Vol. 1), Tokyo: Meijishoin, 1992, figure 11, p. 33. ISBN978-4-625-52137-9
{{Information |Description= {{ja|日本語の四つ仮名の分布図}} {{en|Japanese yotsugana distribution map}} |Source= Made by Enirac Sum, based on ja:画像:Japan pref-16c.png and [[:ja:画像:Japan map.