Hello teachers,
I don't know how to say that some of Iranian people can speak Azeri.
Would you please help me with it? If you were me, how would you say it? (I want to use 30000000 in my sentence)
I searched it in the forum but couldn't find a helpful thread related to my question.

1. 30 million Iranians' mothers tongue is Azeri.
2. 30 million Iranians' mothers' tongue is Azeri.
3. 30 millions Iranians' mothers tongue is Azeri.
4. 30 million Iranians' mothers' tongue is Azeri.
5. 30 millions Iranians' mothers' tongue is Azeri.
6. 30 million of Iranians' mothers' tongue is Azeri.
7. 30 millions of Iranians' mothers tongue is Azeri.
8. 30 millions of Iranian population's mother's tongue is Azeri.
9. 30 millions Iranian population mother's tongue is Azeri.

(I got confused and don't know how to say it)

No source/Self made
Many thanks in advance.