Hello Rohit,

The lecturers can teach either in English or In Hindi.they choose the language in which they find teach easily.

Some professors may speak and teach in english because they might feel better communicating in english with the students but if a student asks a question in hindi they do reply the answer in hindi too.

While some professors teach in hindi because its easier to make people understand things faster using their common language.

But one should also learn and try to communicate in english,this is not necessary but can be helpful in some or the other ways.

You can also ask the proffesor to teach you in the language you find easy to understand, he will surely help you

If we talk about cell phones, no professor allows student to use their cell phone during the lecture for their personal use but if a professor wants to share something or teach something using your phone he can ask and allow you to use your cell..

Except during the lectures you are allowed to use your phone everywhere.

You can even use your phone in hostel also.

It is very common nowadays.