Is the change from “m” to “n” within the descent from O.E.“æmette” to E.“ant” a regular one?

Question

According to Etymonline,I can't help wondering whether there is any other example like this? Because E."emmet",which preserves the "m" intactly,is the cognate of E."ant",which "changed" the "m" to "n" and is "contracted"?

ant (n.) c.1500, from Middle English ampte (late 14c.), from O.E. æmette "ant," from W.Gmc. *amaitjo (cf. O.H.G. ameiza, Ger. Ameise) from a compound of bases *ai- "off, away" + *mai- "cut," from PIE *mai- "to cut" (cf. maim). Thus the insect's name is, etymologically, "the biter off." As þycke as ameten crepeþ in an amete hulle [chronicle of Robert of Gloucester, 1297] Emmet survived into 20c. as an alternative form. White ant "termite" is from 1729. To have ants in one's pants "be nervous and fidgety" is from 1934, made current by a popular song; antsy embodies the same notion.

emmet "ant," from O.E. æmete (see ant), surviving as a dialect word in parts of England; also, in Cornwall, a colloquial name for holiday tourists.

Answer 1

The consonant change from emmet to ant is known as assimilation.

The consonant [m] is both bilabial and nasal and [t] is neither. This makes the consonant cluster [mt] difficult to pronounce because you have to change both features simultaneously (i.e. open your lips at exactly the same moment as you redirect the flow of air from your nose to your mouth). It is easier to change these features one at a time, resulting in the intrusion of a [p] (leading to [mpt]), or else drop the bilabial feature altogether (leading to [nt]). You can see from etymonline that both of these simplifications have happened at different places and times.

Here's John C. Wells in Accents of English (page 96):

A way of reducing the articulatory complexity of strings of consonsants is through assimilation, the process whereby a sound is made phonetically similar to the sounds constituting its phonetic environment. We know, for instance, that the word which is nowadays ant /ænt/ had an Old English form æ̅mete; regular vowel developments would give a present-day form *amt /æmt/ (compare traditional-dialect emmet). The change from [m] to [n] before following [t] is an assimilation which results from an obvious articulatory simplification, namely the elimination of a labial movement.

Some other words which have undergone assimilation include:

• accurate, affirm, etc., from the Latin prefix ad–.
• embody, embolden, etc., from the French prefix en–.
• impossible, impartial, etc., from the Latin prefix in–.
• comfortable, composition, etc., from the Latin prefix con–.
• symphony, sympathy, etc., from the Greek prefix syn–.