The Deng are represented in two equivalent ways for Chinese and
Western writers. The first uses Chinese numerals, 一, 二, 三 and 四,
whilst the others use the capitalised roman numerals I, II, III
and IV respectively. Some authors think that each Division
represents one type of main vowel type. Others think that there
is a difference in palatisation (due to the a [i] glide or
medial) between the Divisions. It is thought that Deng I and II
are the least palatased, whilse III and IV are more palatised.
Of the latter, IV is most heavily palatised, and the vowel there
is reflected by being higher than that in Division III.
Similarly, the vowel in Division II may be higher and more
fronted than that of Division I. This is more or less the view
put forward by Bernhard Karlgren. This can be summarised as
follows. |Division I||Low main vowel.| |Division II||Slightly
fronted and/or higher main vowel than for Deng I.| |Division
III||Palatised low/central main vowels| |Division IV||Strongly
palatised with more fronted highe