Height is one of the three distinctive features of vowels. This blog post will explain the different levels, used in English, and list the English vowels that occur at each elevation.
The height of a vowel is the degree to which the tongue is raised or lowered when articulating a sound.
High = high vowels are said when there is little space between the tongue and the roof of the mouth. Ex. b(ee)t, b(00)t, b(i)t, b(oo)k
Mid = mid vowels are said when there is medium space between the tongue and the top of the mouth, in between closer to its resting position. Ex. b(e)t, (a)ppeal, (u)p, (awe), pill(ow), ch(a)otic
Low = low vowels are said when there is large space allowed in the mouth. Ex. b(a)t, h(o)t