Thanks for the invite Marco.
Most Asians aren't native English speakers. So, no need to worry. But knowing English will certainly help. You don't have to be an expert in English language, but if you are able to communicate well in English you don't have to worry.
If you are planning to come to India, knowledge of English is definitely a plus. We have 2 official languages at national level (English & Hindi). And given that states can have their own languages, there are 22 other official languages in India. If you move from one state to another, you will find people using a different local language. But everyone will understand English, even though it's not their native language.
The bottomline is that Asians don't expect you to be fluent in English. If you are able to read and write English (up to a decent level), you won't face many hurdles.