Know first of all that they are optional, one generally writes the texts without these vowels, which was the case for the text of Lesson 3.
There are four of them:
"a" : it is written with the top of the letter.
"ou" : it is written with the top.
"i" that is written below the letter.
Voyelle muette : it is written with the top of the letter.

here an example :
The letter B with these four vowels is :

Ba

An example of sentence with the vowels:
Omar wrote KATABA 'OUMAROU

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There are of them three: A, OU and I.

Examples:
MADHA = WHAT
NOUROU = LIGHT
'IDI = MY NAME DAY

Note:
These three letters are in the same time are vowels and consonants (semivowels). When it do not play the part of vowels, it behaves like the remainder of the consonants, and thus can 'porter' of the short vowels.

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At the end of the word, the vowel can be short, and certain times (according to grammar) doubled.
I.e. of the form:

Note: the double consonant "AN" is always followed of Alif "A". We will write for example:

NOURAN NOURIN NOUROUN

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