How to pronounce irregularities in American English

Stress falls on the fourth syllable — say "LAIR" with a longer, fuller vowel and keep every other syllable short and quick. The respell "uh-reh-gyuh-LAIR-uh-teez" marks the stressed syllable in capitals so the rhythm is easy to read at a glance.

In American English, when /t/ sits between two vowels with the second one unstressed, it turns into a quick D-like flap. So "irregularities" sounds closer to "uh-reh-gyuh-LAIR-uh-teez" than to a crisp-T pronunciation. This is the flap-T rule, one of the most distinctive sounds of casual American speech.

Unstressed syllables in American English collapse toward a schwa — a lazy, neutral "uh" sound. The full vowel is what textbooks teach, but in actual American speech every unstressed vowel reduces. The respell "uh-reh-gyuh-LAIR-uh-teez" shows the reduced form so you can hear the casual rhythm directly.

Americans use a relaxed retroflex R: the tongue curls back rather than rolling, and the R is one continuous sound with the vowel before it — not two separate sounds. Don't try to pronounce a separate vowel followed by a separate R. Treat them as a single shape.