I saw a question that said are there any words w/o vowels?

Lots of people ( most) said dry, cry, sty, my, , Don't they teach tghat vowels are a e i o u and sometimes Y? In these worrds that function as the vowel. what do you think. ? One girl said pssst ( like -be quiet) she was the closest but that is more of a symbol of a sound.