trill

A note that alternates rapidly with another note a semitone above it.

The articulation of a consonant (especially the consonant `r') with a rapid flutter of the tongue against the palate or uvula.

“he pronounced his R's with a distinct trill”

Sing or play with trills, alternating with the half note above or below.

Pronounce with a trill, of the phoneme `r'.

“Some speakers trill their r's”