Air is forced through a narrow passage, creating friction (e.g., /f, v, s, z, ʃ, h/).
Obstruents frequently occur in pairs—one voiced (vocal folds vibrate) and one voiceless (no vibration)—such as /s/ vs. /z/ or /t/ vs. /d/. obstruent
They are marked by the presence of noise or silence during the constriction phase. Air is forced through a narrow passage, creating friction (e