from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The insertion of a sound in the middle of a word, as in Middle English thunder from Old English thunor.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The insertion of a phoneme, letter, or syllable into a word, usually to satisfy the phonological constraints of a language or poetic context.
from the GNU version of the Collaborative International Dictionary of English
- n. The insertion of a letter or a sound in the body of a word.
from The Century Dictionary and Cyclopedia
- n. In grammar, the insertion of a letter or syllable in the middle of a word, as alituum for alitum.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the insertion of a vowel or consonant into a word to make its pronunciation easier
In other words, epenthesis is likely to be unnecessary.
This epenthesis is seen elsewhere, as in Herecele where its Greek origin emphasizes that this phonetic process did indeed happen.
I notice that Mongolian also has a similar process of left-to-right schwa epenthesis however this seems to occur to resolve clustering in the coda not the onset.
So ideally you want to find a noun with a-epenthesis that will correspond in root with a verb, and see what happens?
Unlike a totally unproven epenthesis, rules concerning sonorancy prove its absence in at least one case.
So... we see that offending verbs like these did not survive intact and yet were not resolved by metathesis or epenthesis.
I might also be interested to find out that vowel insertion is widespread enough in the world's languages to have a name, epenthesis also called anaptyxis.
Maybe I could observe that epenthesis happens as a rule in English plural formations when the singular form of a word ends in an "s" sound; thus the plural of kiss is not kiss-s but kisses.
Among phonetic changes which occur with more or less regularity are those called aphesis, epenthesis, epithesis, assimilation, dissimilation, and metathesis, convenient terms which are less learned than they appear.
But epenthesis of a consonant is more common, especially b or p after m, and d after n.