古咸、山摄开口一等在粤语(含桂南平话)中主元音的今读类型可分为央元音、圆唇元音和展唇前元音三大类型。其中,前两型多仍保持古咸、山开口一二等见系主元音的对立,而后一型型则多属于一二等主元音合流的方言。其成因与早期后低元音的不稳定性及声母、韵尾、声调、音韵格局的制约都有一定的关系。文章发现:(1)粤语属于谈覃不分以及咸山开口一二等非见系主元音合流的方言;(2)多数粤语仍保留古咸山一二等见系主元音分立的局面,部分粤语有合流现象是较为晚近的音变。 Ancient salty, mountain photogenic openings in Cantonese (including Guinan Ping dialect) in the main vowels of the present reading type can be divided into central vowel, round lip vowel and exhibition lip vowels three types. Among them, the first two types are still more ancient salty, mountain openings one or two see the opposite of the main vowel, and the latter type are mostly one or two other main vowel convergence dialect. Its causes are related to the instability of early low vowels and the restriction of initials, endings, tones and phonological patterns. The article finds that: (1) Cantonese belongs to the dialect of non-seeing Tan and Yanshan openings and other non- , Some Cantonese convergence has a more recent sound change.