Answer: 4:11
Step-by-step explanation:
Given : Fraction of students study a language 
Let x be the number of students in the school.
Then , No. of students study a language 
Fraction of students who study a language study French 
No. of of students who study a language study French 
No. of students study French =
Then, the number of students do not study French = 
Now, the ratio of student who study French to students who do not study French:-

Hence, the required answer = 4:11