Which phone is produced with an obligatory constriction in the pharyngeal cavity?

• A. [h]
• B. [ŋ]
• C. [k]
• D. [ɹ]

Answer: (D)

The key idea is that a pharyngeal constriction means narrowing the airstream in the pharynx, the space behind the oral cavity. The rhotic approximant [ɹ] is produced with a constriction in the pharyngeal region—the tongue forms a narrow passage near the pharyngeal wall (variants exist, like retroflex or bunched shapes, but both involve pharyngeal narrowing). This pharyngeal constriction is a defining feature of rhotics in many phonetic descriptions, giving them their characteristic r-like quality.

In contrast, [h] is built at the glottis (a glottal fricative), [ŋ] is a velar nasal with a velar constriction, and [k] is a voiceless velar plosive, involving the velum. None of these require a constriction in the pharyngeal cavity as their defining articulatory feature.