You mightn't be able to understand them
French do not speak a different language: they all or nearly all speak French. The people who do not speak French, are the ones using a different language.
So you can speak to people who don't speak your language.
Yes, the people in Italy speak different languages than the people in America.
They speak a different language, Slovak.
They speak a different language, Slovak.
So you can speak to people who don't speak your language.
To talk to people in different languages, get someone you know who CAN speak that language. If you don't know anyone, get their dictionary and try to speak their language
People in Melanesia speak the pidgin language because Melanesia includes many islands with people that speak different languages, so some people combine the languages to make the pidgin language.
Most New Yorkers speak English, but you have to remember that people from all over the world live there, so some people may speak a different language.
If you can only speak one language that's fine because it suits the environment that you live in but if you speak more than one language that's even better because you can speak to foreign people and will be able to speak a particular language when you go to a different country.
ancient people spoke thousands of different languages.
Not necessarily. A language family can have dozens of different languages in it.