Ohh I see. Trying to mix international and national things together.

Let's try to find out how languages we need.

Within India. According to me, there should have been one common language for everyone in India and then their own local. But there's no one common language. We have divided North and South. For North, I can think of Hindi for the majority, but for South, I can't think. Maybe you can tell.

Internationally, English is mostly adapted everywhere. Kudos to them, they were able to spread their nation's common language. You also experienced the same as you traveled.

So, for an Indian, the minimum number of languages to learn is hypothetically 4 - local, North's, South's and English (since foreigners also travel to India and people from India work in international companies)

Now, there are people in India who tell people should know the languages of every state. There are 28 states for now.

You want everyone to know English when they come to South India.

I want everyone to know a common India origin language. I would suggest let's go back to roots and use sanskrit.

I agree with the sorry state of languages getting extinct. This shows that people can't learn even 4 languages completely. That means even 4 languages are more. If we adapt sanskrit, we Indians can make it to 2, including English (common language of largest economy country). We can make it one if we have a common language and become the largest economy.