Hey aspirant

According to reviews,

You will be learning Hindi at NDA if you did not study it in class in grade ten. While the other cadets can choose between French, German,  and other languages, you will be forced to learn Hindi.

Apart from officially including Hindi in your curriculum, your seniors will make it a personal goal to teach and converse with you in Hindi. Some are genuinely trying to improve your language skills, while others are simply having a good time at your expense (like Chatur, in 3 idiots). In any case, whether you like it or not, you'll learn Hindi.