The vowels

The vowels in English language are ...a..e..i..o...u

and sometimes...y... as it acts like it...
They are called vowels because their respective sounds which amount to 12 are produced with the free passage of air from the mouth to the larynx...at no time does anything within the mouth(the tongue) or the larynx or the lips touch...
The other sounds from the consonants all have something touching when being produced.