Which of the following is NOT a place of articulation?

The correct answer is distinguished by understanding the definition of place of articulation in phonetics. A place of articulation refers to the specific location within the vocal tract where airflow is constricted to form different speech sounds. Examples such as bilabial (involving both lips), velar (involving the back of the tongue and soft palate), and interdental (involving the tongue and the space between the teeth) all specify locations in the mouth or vocal tract where articulation occurs.

On the other hand, 'sibilant' refers to a characteristic of certain sounds, particularly the high-frequency hissing sounds associated with fricatives like /s/ and /z/. While sibilants are a class of sounds identified by their acoustic properties, they do not indicate a specific point of constriction or articulation, which is why this term is not classified as a place of articulation. Recognizing the difference between these concepts is crucial for understanding phonetic terminology.