This is a right accepted by the United Nations. However, there is no free speech in the world, and internet is the best example. I am not talking about security against governments, organizations, and the like - there we need cryptography. I am talking about the right to say what you want to everyone that wants to listen to you. There is no free speech if people cannot understand you, and here we have found the problem of language.
Translation is a difficult task, sometime called an 'art', and it can also be very expensive.
Prices vary widely from case to case, but there is no good, inexpensive translation service available anywhere. The second option could be a good one. If one person has to renounce the right of speaking in his or her native language, the other should do the same. Spanish-speakers in the US are a good example, but I remember when once, on Internet, I witnessed an American heckling a Romanian who was trying to write in English and making stupid mistakes. Many people who could not only solve problems or work together but also make friends cannot do this now because they can't communicate.