What role does "articulation" play in singing?

Articulation in singing is crucial because it directly impacts how clearly words and notes are expressed. It encompasses the way in which singers shape their phrases, including the initiation and release of sounds, which in turn enhances the intelligibility of the lyrics and the overall musicality of the performance. Proper articulation allows the audience to understand the text and emotional nuances conveyed through the song, making it a vital aspect of effective communication in music.

The other roles mentioned in the options relate to different aspects of musical performance. For example, the key of a piece refers to the tonal center around which the music is organized and is unrelated to how the words are articulated. Tempo pertains to the speed at which music is played or sung, which does not affect the clarity of articulation. Pitch, which defines how high or low a note sounds, also remains separate from how clearly the notes or words are articulated. Thus, articulation stands out as specifically focused on clarity of expression in singing.