QUEL / QUELLE

Quel / Quelle are interrogative adjectives which mean what? or which? .

In English,  we always use the same interrogative pronouns : which/what. 

 In French, however,  we have more varieties. The interrogative pronoun quel changes ; depending on the word it is referring to. In other words; it agrees in gender and number with the noun it describes .

French interrogative adjectives :

Example : 

Vous avez quel age?                                  What is your age?

The word age is masculin, So , Quel is used.   

Quelle est votre profession?                     What is your profession?

The word profession is feminine, So , Quelle is used.                  

Quels livres va-t-elle acheter ?                Which books is she going to buy?

The word livres is masculine, So , Quels is used.

Tu parles quelles langues?                       Which languages do you speak?

The word langues  is feminine and plural, So , Quelles is used.  

The rules :

Other questions that you can use with quel / quelle   :

Quelle est votre / ton adresse ?                                                      - What is your address?

Quelle est votre / ton adresse email  ?                                         - What is your email address?

Quel est votre / ton numéro de telephone ?                               - What is your phone number?

Quelle est votre / ta nationalité?                                                    - What is your nationality?