Sounds of vowels:

A vowel is a letter of the alphabet (a, e, i, o, u, and sometimes y) that represents a speech sound created by the relatively free passage of breath through the larynx and oral cavity. Letters that are not vowels are consonants.

As pointed out below, spoken English has approximately 20 distinct vowel sounds, though there are dialectal variations.

                                                                                 

A dialect is a regional or social variety of a language distinguished by pronunciation, grammar, and/or vocabulary. 

Adjective: dialectal.

The term dialect is often used to characterize a way of speaking that differs from the standard variety of the language. 

Consonants:

A consonant is a speech sound that's not a vowel. The sound of a consonant is produced by a partial or complete obstruction of the air stream by a constriction of the speech organs.
In writing, a consonant is any letter of the alphabet except a, e, i, o, u, and sometimes y.