In several instances French loanwords affected the English sound system. The sounds [v] and [f], for example, had been allophones of /f/ in OE, but in ME they became separate phonemes. In OE, [v] and [f] never contrasted. The [v] would appear only in the middle of an OE word. However, the French word ver “spring” would on entering ME in its French form contrast minimally with OE feor > late OE fer “far” and thus create a phonemic distinction between /f/ and /v/. To put it simply, ME speakers learnt to hear the difference between the initial [v] in Early ME ver and the initial [f] in Early ME fer. Thus, the phonetic difference [f] – [v] assumed phonemic status and [v] was, so to speak, promoted from allophone to phoneme.

In another instance Anglo-French bilingualism could have been the reason for simplification of the Anglo-Saxon consonant clusters with [h], such as hn, hl, hr and hw (as in hnappian – to nap, hlaf – loaf, hring – ring and hwæt – what). Such clusters would have been strange for bilinguals who could have started the process, which led to the elimination of [h] from initial clusters by the fourteenth century. Only hw still survives in the speech of some older RP users in words like what and which. It is also found in Scots and in the speech of some New Zealanders.