Excrescent -t in Amongst and Whilst Part II

Against is one word in which the excrescent -t has become entirely standard. The Middle English form of the word had been aȝænes or aȝeins; thereafter, according to OED,

     Late in the 14th century, after the -es had ceased
     to be syllabic, the final -ens, -ains developed in the
     south a parasitic -t as in amongs-t, betwix-t,  
     amids-t, probably confused with superlatives in -st
     and c. 1525 this became universal in literary English.

This theory that prepositional forms were modelled after superlatives, i.e., that excrescent -t developed by analogy with -est forms, is interesting. 

In particular, I'm inclined to think that the word next may have had an important role to play in this process. Most English speakers are now unaware of this, but next is a superlative. The Old English for "near" was neah; our positive form near is in fact the comparative form of neah; our present next developed from the superlative form neahst.

Next is also an adjective. But its meaning, having to do with relations of space and ordinality, is sort of quasi-prepositional. Perhaps the excrescent -t that became standard in the preposition against was bolstered by the example of next, especially as awareness of next's superlative nature waned in the minds of speakers.

So while (or whilst) it bugs me perennially that amongst and whilst are preferred by some writers over the manifestly briefer and morphologically "cleaner" among and while, I can certainly see why these forms were an inevitable outgrowth of amongs and whiles, especially as speakers of English began to lose their intuitive grasp of the adverbial genitive -s.

In sum, there were two (maybe three) factors that drove the development of forms like amongst and whilst. One, the tendency to sound a homorganic plosive after the [s]; two, the analogy of superlative forms, especially, perhaps, next; and, three, a grammatical uncertainty about  -s endings and an impulse to make these words align with a better understood form.

Incidentally, the process continues today. I have heard a number of people say acrosst for across.