Kutchi language at Schools

I had a discussion today with one of my colleagues, whether Kutchi should be spoken at schools of not.
Some of our colleagues speaks kutchi to communicate with students as the students feel comfortable. But in my views it is not a good practice. The first and foremost point is that students do come at school to learn various subjects (which are in Gujarati language) and Gujarati language itself is one of their subject.
Kutchi is not a Language. It doesn't have grammar or alphabets. So keeping them away from Gujarati has no sense. Some teachers think that they are being friendly with students by speaking kutchi but  Doing these we are harming them.
Students needs to increase their  Gujarati vocabulary because its needed for them in future. They need to write their papers in Gujarati not in kutchi.

So, for the purpose of students own benefits, we should make a practice to speak and make the students speak Gujarati at school. And teacher or parents should not relate it with prestige or harm to kutchi language.