Different of Constant and vowel sound

[gihanr]

I don't have a clear idea about the different between consonant sound and a vowel sound. So I make mistakes when using Articles. Please help me to correct this.

Sorry about the topic. It has to be consonant instead Constant. Sorry.

[Soup]

One difference between consonants and vowels is that you can sing vowels.

Vowels: a, e, i, o, u,

Special note, in some words, the letter <u> has a vowel sound, for example,

umbrella => an umbrella

but in other words the letter <u> has a consonant sound, as in

USA => a USA newspaper.

<U> is pronounced yu, with a consonant.

Note also that, some consonants have a vowel sound. The letter <m> for example:

MBA => an MBA course

The letter <M> is pronounced em, with a vowel.