@RecDiffs The linguistic training I have makes me want to say that it's I don't think it's the glottalized t sound alone, which is very common, but that this happens alongside the schwa which sounds really very low and back to me, like maybe a weird combination of these fairly recent phenomena:

https://en.wikipedia.org/wiki/California_English#California_vowel_shift
https://en.wikipedia.org/wiki/Phonological_history_of_English_close_front_vowels#Pin–pen_merger
https://en.wikipedia.org/wiki/Phonological_history_of_English_close_front_vowels#Weak_vowel_merger

I can't explain why it makes them sound like a baby though, but it really does.

@hotdogsladies @instantiatethis @RecDiffs

Once you realize all of these phonological processes you can't help but notice taht everyone sounds like lazy baby/bumpkin no matter how smart they are. The worst one for me was when I realized how I say the word 'commercial'...

@sjtrny @RecDiffs it's not that -- I'd say a new use of a common General American English feature.

https://en.wikipedia.org/wiki/T-glottalization#Glottal_reinforcement_(pre-glottalization)

Speakers unconsciously reanalyze word phonology all the time, and so Merlin’s ‘important’ is [ɪm.ˈpʰɔɹ.tənt] and the new one is [ɪm.ˈpʰɔɹʔ.n̩ʔ/]. The /t/ was once initial in the last syllable, but is now undersood as syllable-final in the second syllable, and so comes out as glottal stop. Also, because the last syllable has no onset, it becomes syllabilized /n/ ([n̩]).