Voiceless alveolar fricative

A voiceless alveolar fricative is a type of fricative consonant pronounced with the tip or blade of the tongue against the alveolar ridge (gum line) just behind the teeth.

Voiceless alveolar sibilant
The voiceless alveolar sibilant is a common consonant sound in vocal languages.

Voiceless alveolar non-sibilant fricative
The voiceless alveolar non-sibilant fricative (also known as a "slit" fricative) is a consonantal sound.