Language is part of human communication and used for expressing difference emotions such as pleasure and anger. These strange noises are called words and often consists of sounds. Some may say we are dumb as animals but we are sometimes. Even animals talk to each other and were are too stupid to realize. Earth has many languages and dialects.
There are millions of languages on Earth and took a long time to even write down every single one of them.
Also linguists are sometimes more likely to make a mistake and not record every single word from each language resulting in some trouble with communicating with many people.