What the voicing of air from a mouth (without syllable) called? For example when we say the consonant "sh" without a syllable. It's usually happens when you want to quiet a child or something like that (it's almost like a whistling, but it's not exactly the same, or maybe it's a kind of whistling). In some cultures when one wonders on somethings bad or huge he may make such sound. I'm looking for the name for this sound.
It's not exactly clear what you mean. When you say "shh" to someone to quiet them, that's called "shushing." When you emit voiceless white noise from your mouth like an H sound, that's called "hissing."