Press your lips together. Air flows through your nose. Vocal cords vibrate.

Americans pronounce mediator as MEE-dee-ay-ter (/ˈmidiˌeɪɾər/). In "mediator", the "t" between vowels sounds like a quick "d" — the tongue briefly taps the ridge behind the upper teeth. This is called the Flap T, and it's one of the defining features of casual American English. So instead of MEE·tee·ay·ter, you get MEE·dee·AY·ter. Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "The mediator helped them reach a mutually beneficial agreement".
Record yourself saying "mediator" and play it back. The mic stays on your device — nothing's uploaded.
4 syllables, 7 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
The textbook way isn't wrong — it's just not how anyone actually says it.
In "mediator", the "t" between vowels sounds like a quick "d" — the tongue briefly taps the ridge behind the upper teeth. /t/ or /d/ becomes a quick tap [ɾ] — sounds like a soft D. The tongue briefly taps the ridge behind the upper teeth.
Stress falls on the first syllable, not the others. Stretch MEE — keep everything else short and quick.
Americans use a relaxed retroflex R — the tongue curls back rather than rolling. The R is one continuous sound with the vowel before it, not two separate sounds.