Which statement best defines acoustic phonetics?

• A. The physical properties of speech sounds as produced with the articulators.
• B. The smallest units of speech, including phones and features.
• C. Speech sounds as transmitted through the air in the form of sound waves.
• D. The sound system of the language.

Answer: (C)

Acoustic phonetics focuses on the speech signal itself—the physical energy of speech as it travels through the air as sound waves. It examines how those waves carry information about pitch, loudness, duration, and the spectral content that helps distinguish sounds. This is why the best description is the one that talks about speech sounds transmitted through the air in the form of sound waves. The other statements point to production with the articulators (articulatory phonetics), the abstract units and features used in language analysis (phonology), or the overall sound system of a language, rather than the physical acoustic signal.