Why was it necessary to divide alphabets into vowels and consonants?

Question

This may be an extremely simple question. I know pretty much what do we do when we see any vowel but I am curious why were these two classes created in the first place.I beg pardon for another question : Why were only these letters chosen as vowels :**a , e , i , o , u** ?

Answer 1

Alphabets are developed for already existing spoken languages. The separation of consonants and vowels exists because vowels are the louder parts of speech (because our mouths are open wider when saying a vowel than a consonant) and they assist in teaching spelling by helping us distinguish syllables.