How exactly to pronounce 'alphabetical' and 'pharmaceutical' in American English [closed]

A t in the middle of a word is often pronounced as a soft d in American English. (I think the sound is technically known as a flap or tap.) In both of the words you've asked about, most Americans are likely to make a sound closer to a d than a t.

This page has some sound files with flapped and un-flapped t's, if you'd like an example of what that sounds like.

These words are not pronounced with d in American. They are pronounced with an alveolar flap. In general American, this consonant replaces both t and d when they lie between two vowels, the first of which is stressed, and it sounds very much like a d to British ears.

If you pronounce these words with a regular t, Americans will understand you perfectly, although it will contribute to an impression of a foreign accent (my guess is that it would sound like a very slight Spanish accent if you pronounce everything but these t's and d's the way Americans do). If you pronounce these words with a regular d, I believe Americans would be more likely to misunderstand you, although I don't know whether anybody has studied it.