Gugerell-Scharsach (1992) is an attempt to discover whether the Middle English WM dialect as defined by Moore, Meech and Whitehall (1935) can be traced in the SED material. Glauser (1997: 93) notes that Moore, Meech and Whitehall defined their WM dialect with the help of a single phonological feature, ME /o/ before nasals, locating it in a semicircular territory with the Welsh border as its diameter and reaching as far east as Derbyshire and Warwickshire. Glauser further notes that 19th-century evidence in favor of a single WM dialect is scanty, with Wright (1905) showing no east-west divide at all, Bonaparte (1875–1876) setting up an area similar to the ME one, and Ellis (1889) delimiting the WM with the aid of the criterion used by Moore Meech and Whitehall. Glauser says the SED still documents TRAP/BATH rounding before nasals in much the same area Moore, Meech and Whitehall did, but notes (1997: 95) that Gugerell-Scharsach finds herself able to identify (partially using phonological data) three main WM dialect areas from the SED data, namely a Staffordshire, a Shropshire and a Southern WM dialect. Of these, the dialects of the WM urban conurbation are likely to constitute the latter grouping.

Brook (1972: 68–69) claims that certain phonological features can indeed be taken to be characteristic of a WM (traditional) dialect area, the most important being:

(1) Retention of late ME  as WM , where other dialects have  (e.g. in among, hang, sing, tongue);

(2) Rounding of ME /a/ and /o/ to WM  before nasal consonants, where other dialects have [a ~ æ] (the correlation highlighted by Moore, Meech and Whitehall 1935). However, Wakelin notes (1981: 164) that in parts of the WM, with great variation from word to word,  occurs in other positions also (e.g. rat, apples, latch); also Brook (1972: 68) points out that OE /a/ before nasals remained /a/ under non-heavy stress);

(3) OE /o/ tended to become ME /u/ before .

Chinn and Thorne (2001: 22) propose that the WM accent once had much more in common with general Northern speech, but has been gradually pulled in the direction of prestige Southern variants.