Labialization is the replacement of a non-labial sound by a labial one.

• A. Replacing a nasal with a stop
• B. Replacing a consonant with a vowel
• C. Replacement of a non-labial sound by a labial one
• D. Replacing a stop with a fricative

Answer: (C)

Labialization involves articulations with the lips. A labial sound is made with the lips, and when a non-labial sound is replaced by a labial one, the place of articulation shifts toward the lips as part of the sound change. The statement in question matches this exactly: it describes replacing a non-labial sound with a labial one, which is the essence of labialization.

Understanding this helps distinguish it from other types of changes. For example, turning a nasal into a stop is a change in manner, not specifically about moving the articulation toward the lips. Replacing a consonant with a vowel is vowelization, a different process altogether. Replacing a stop with a fricative also changes the manner of articulation, and isn’t defined by introducing a labial placement.

So, the best description is the one that directly names changing a non-labial sound into a labial one, since that captures the core feature of labialization: the involvement of the lips to create a labial articulation from a non-labial source.