when the vocal cords move apart, th

when the vocal cords move apart, the glottis is wide open, it is called open glottis. this happens when human is breathing and when the voiceless sounds are produced. if the vocal cords stick to each other, the opening is not formed. then the position is closed glottis. air from the lungs will be stopped at the vocal cords. no air allowed to get through them. at this point it can be the beginning of a particular sound called glottal stop as in a Thai vowels "ะ". the other position is when the air is stopped at he vocal cords, the pressure happens. it causes power to quickly move the vocal cords on and off, therefore a small amount of air is continually letting out at a time. the vocal cords then vibrate. voiced sounds are formed/b,d,m,n,v/ and all vowel sounds in English.