Institutio Oratoria

Hence we get forms such as belligerare and pomeridiem, to which the diee hanc [*](i.e. for belligerares, postmeridiem and diem hanc. ) of Cato the Censor, where the final m is softened into an e, presents an analogy. Unlearned readers are apt to alter such forms when they come across them in old books, and in their desire to decry the ignorance of the scribes convict themselves of the same fault.

On the other hand, whenever this same letter m comes at the end of a word and is brought into contact with the opening vowel of the next word in such a manner as to render coalescence possible, it is, although written, so faintly pronounced ( e.g. in phrases such as nultum ille and quantum erat ) that it may almost be regarded as producing the sound of a new letter. [*]( A very probable account is that -m was reduced through the lips not being closed to pronounce it. If, instead of closing the lips all that were done were to drop the uvula, a nasal sound would be given to the following initial vowel, so that fine onerat would be pronounced finewonerat with a nasalized o. Lindsay, Lat. Langu. p. 62. It is this sound which Quintilian describes as almost the sound of a new letter. ) For it is not elided, but merely obscured, and may be considered as a symbol occurring between two vowels simply to prevent their coalescence.