Patter song is characterized by fast or very fast tempo. it's a comic song which depends on its rapid expression of words. most commonly it occurs in an Operetta. so the answer to your question is Operetta.
<em>You may expect to find a pattern song in an Operetta.
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Operetta is a musical production, a genre of the performing arts which usually has a romantic plot, includes songs along the play, dancing, orchestra, and dialogues. It is related to Opera but it is much lighter in the music style and the plot. Operetta derives from Italian comedian plays of the 16th century, the ballad opera, famous in England, and even the French Vaudeville.
