Are there multiple valid pronunciations for ing or present participle form of boggle -- [bog-uh l] | /ˈbɒg əl/? I.e. are both of the following valid for boggling (not thinking of bogglin or other shortened pronunciations)?
If the second form is valid, are there specific dialects where it's common? Otherwise, is there a term for this type of mispronunciation?
Epenthesis is the insertion of a consonant or vowel, usually to ease pronunciation, as in the p-sound most speakers use in ham[p]ster, or for those who find thl a bother to pronounce, the insertion of a schwa in ath[e]lete.
Now your particular case is somewhat different, since retaining a vowel otherwise elided is not the same as inserting it where it never was to begin with. It could be argued that in the present participles – or other derivatives such as agent nouns in -er – derived from verbs ending in -le, the elision is very common, but not mandatory. While most native speakers would pronounce toddler with the elision, toddling sounds more natural to me without it. At any rate, I don't think the non-elided form of such words is so deprecated that it would be considered an error. In other words, a matter of opinion.
A similar case is the tendency of some native speakers not to pronounce vocalic n in contractions such as didn't, wouldn't, or couldn't, instead inserting a schwa or lately even a fronted vowel before the n, or in words ending in -ant where vocalic n would otherwise be expected, like important. (Take that, Ezra Klein! See this video at 1:40 mark) While this particular pronunciation puts my teeth on edge, enough educated elites use it in their podcasts that calling it an error rather than a new variation seems ill-advised.
