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"
口蓋または口蓋垂に対する舌の急速な振るえによる子音(特に子音『r』)の明瞭な発音
trill
pronounce with a trill, of the phoneme `r'; "Some speakers trill their r's"