蒲立本
Some linguists prefer to reduce the number of vowel phonemes further (at the expense of including underlying glides in their systems). Edwin G. Pulleyblank has proposed a system which includes underlying glides, but no vowels at all. More common are systems with two vowels; for example, in Mantaro Hashimoto's system, there are just two vowel nuclei, , which may be preceded by a glide , and may be followed by a coda (additional sequences are afforded by the rhotic coda ; see Erhua). The various combinations of glide, vowel, and coda have different surface manifestations, as shown in the table below. Any of the three positions may be empty, i.e. occupied by a null meta-phoneme ; for example, the high vowels are analyzed as glide + , and the empty rime, i.e. the syllabic consonant or the vowel , is analyzed as having all three values null, e.g. "si" is analyzed as an underlying syllabic .