N+ T Assimilation in natural Mandarin
I think that a lot of these phenomenons that you are describing among the different questions you’ve asked recently and especially this one, have something to do with:

连读

This is similar to a liaison in linguistics. I’m not sure if this is, in actual fact, the correct term or not, but it is at least what a layman might call it.

This is a particularly northern way to speak. Some examples include:


意思 = yisss / here 思 has its /s/ sound merged right into the of “yi”
认识 = rensh / almost sounds like the English “wrench,” again the /i/ gets obliterated


I asked a similar question before here:
Where can I find a list of (acceptable) 连读 words?
You can have a look and see if it helps you any.