What is obstruent vs sonorant?

Obstruent and sonorant are two categories of sounds in phonetics.

Obstruent sounds are produced by obstructing the airflow through the vocal tract, causing a build-up of pressure, and then releasing it suddenly. These sounds include stops (plosives), where the airflow is completely blocked for a short time, and fricatives, where the airflow is partially blocked, causing friction and a hissing or buzzing sound. Examples of obstruent sounds include /p/, /t/, /k/, /f/, /s/, and /ʃ/.

Sonorant sounds, on the other hand, are produced with a relatively open vocal tract, allowing the air to flow freely through the mouth. They are typically voiced sounds, meaning that the vocal cords vibrate during their production. Sonorants include nasals, where the airflow is directed through the nose, liquids, which are produced with a partial constriction in the mouth, and glides, which are produced with a slight movement of the tongue. Examples of sonorant sounds include /m/, /n/, /l/, /r/, /w/, and /j/.

The distinction between obstruents and sonorants is important in phonetics and phonology because it helps to explain some of the patterns of sound changes and word formation that occur in language. For example, obstruent sounds tend to behave differently from sonorant sounds in terms of aspiration, voicing, and assimilation.