Language is one of the most complex inventions of man. It is the power of communicating with others through language that was responsible for seperating man from the rest of the animals and is at the base of human civilization.
Yet language is such a complicated thing, and it is a real wonder how in a small span of few thousands of years, so many languages evolved on earth. And each language is unique. There is a branch of psychology which looks into the aspect of wether language affects the way we think or did the way we think shape our languages. The well known example for this is the presence of more than 20 different words for different shades of white in icelandic language, who are surrounded by ice most of the time. So here obviously, the environment shaped the language. But does an icelander have a better and more complete perception of white than the rest of us?
It is for this reason that learning a language also expands our thought process. For some of the peculiarities of a language can never be translated to another. And once we know a language other than our mother tounge, we are also able to make that mental process involved in that phrase which might not exist in our mother tounge.