The last two letters of the vowels are ஒள and ஃ. These are not used much in modern Tamil. ஒள comes at the beginning of the word and ஃ always comes in the middle of the word.
With this we have finished with all the vowel sounds of Tamil. Get an overview of the vowels we have learnt so far.
Listen to these sounds and repeat them.
Whenever you come across any Tamil writing see how many of these vowels you can recognize and read.