Which phonetic feature most distinguishes the sounds [p] and [b]?

The most distinguishing phonetic feature between the sounds [p] and [b] is voicing. Voicing refers to whether the vocal cords vibrate during the production of a consonant sound.

In the case of [p], it is voiceless, meaning that during its articulation, the vocal cords do not vibrate. In contrast, [b] is voiced, which means that there is vibration of the vocal cords as it is produced. This difference in voicing is a significant phonetic feature that changes the meaning of words in many languages. For example, the difference between "pat" [pæt] and "bat" [bæt] highlights how the presence or absence of vocal cord vibration can create distinctions in meaning.

While place of articulation (where the sound is produced in the vocal tract) and manner of articulation (how the sound is produced, like whether airflow is fully blocked or partially released) are important characteristics, they do not differentiate these two sounds, as both [p] and [b] share the same place and manner of articulation—they are both bilabial stops. Stress is also not relevant in distinguishing these specific sounds. Thus, voicing serves as the key feature that sets [p] and [