Is the second "t" silent in the word "twenty"? [duplicate]

Well, I usually say "twenny" instead of "twenty" (not "twendy" even). I recently noticed that I never heard the same from any native english speakers during any talks I ever had with them.

Recently I had a brief search on the 'net and it seems that it is somehow okay to say "twenny", but it might look the least correct pronunciation for most of the people, or they might think you have strange accent, etc.

So, my question is, is there any good reference which clearly proves saying "twenny" instead of "twenty" is totally correct or wrong?

P.S. You're most welcome to write your very personal opinion if you don't know any good references.

Update

I've already looked at the major dictionaries and didn't find any of them lists "twenny" in their pronunciation's section, however I'm sure that I didn't made that up, but I heard that while ago. Maybe in a movie, maybe from someone, and that's why I'm looking for the answer.

The stop in syllables that end in a homorganic nasal-plus-stop cluster (in English, these clusters are /mb, mp, nd, nt, ŋɡ, ŋk/) is often elided. Word-final /-mb/ and /-ŋɡ/ never occur in Modern English, for example, although their dumb Middle English spellings hang around.

Final /-nd/ does occur, though not always, but it's frequently neutralized with /-nt/, especially after a stressed vowel and preceding an unstressed one. As in twenty.

This interacts with the neutralization of /d/ and /t/ in the same environment; in American English, both go to [ɾ], as in betting and bedding, which differ -- if at all -- only in the allophonic vowel length of stressed /ɛ/ in the first syllable of bedding.

Upshot: In American English, /'twəni/ is the normal pronunciation, /'twɛni/ is somewhat more formal and careful, and /'twɛnti/ is fastidiously careful.

Lexico on BrE: Pronunciation /ˈtwɛnti/
Lexico on AmE: Pronunciation /ˈtwɛn(t)i/

Speakers of English may get lazy and not articulate the second t sound clearly, or at all. However it is non-standard. There are some dialects (for example, London and the Thames Estuary) where it is reasonably common. Because it is non-standard, it appears in writing only when actually representing this speech, as indicated in the Wiktionary entry.

I don't entirely agree with John Lawler's answer, insofar that it seems to suggest that there is little difference between the pronunciation of "twenty" and the pronunciation of any other word with /nt/, or of any word with /nd/. I do believe that the use of a reduced pronunciation without the sound [t] is more common for twenty than for a word like winter, and more common for winter than for a word like grunting (see my answer to the ELL question Can we drop the T sound in word grunting in American English?) And words with /nd/ don't necessarily show the same kind of reduction.

Also, mb, mp, ŋɡ, ŋk behave even less similarly, so I wouldn't group them together with nt or nd.

It's impossible to show that any pronunciation of twenty is "totally correct" or "wrong" because these words don't have any clear and universally accepted definition in this context. The pronunciation without a [t] is attested in the Oxford Dictionaries entry for US English: it gives the pronunciation in IPA as /ˈtwɛn(t)i/, which is just an abbreviated way of writing "/ˈtwɛnti/ or /ˈtwɛni/". As described in this answer by Greg Lee, at least some speakers are supposed to use a nasal flap sound [ɾ̃] in words like twenty. Greg Lee says that he also uses a nasal flap in words like penny, but in a comment, Janus Bahs Jacquet suggested that some speakers might maintain a slight distinction by using [ɾ̃] in twenty but [n] in penny.

Greg Lee also left a comment below that post with an interesting citation about the pronunciation of /nd/ vs. /nt/ in this kind of context:

Stampe has pointed out that for some midwestern speech, there is a level of casualness where "candor" and "canner" differ just in having [n] in the first and nasal flap in the second. The [n] in "candor" comes by an assimilation of the [d] to preceding [n], giving [nn], then a simplification of the geminate.