Due to dominance of certain languages some rare language are fade away from the world every year.
This sentence has some grammar issues.
Due to dominance of certain languages, many rare languages are disappearing every year.Some people believe that less language which has spoken by many people is better important than rare languages.
Many believe that a single language would suffice the world.Having less language in the world helps to travel and communication easier but disappearance of rare language will weaken particular culture.
Having just one language would make travelling and communication much easier for everyone but rare languages have a lot to do with the culture of it's people.Often language is related to culture.
... good point
You need to improve your grammar. :)