Through your life, even if you don't use every word of your language, you come across beautiful poems, you read stories, and the range of the expressions you know is widening. And by knowing many words for (for example) feelings or natural phenomena, when you experience something, you can exactly understand that expression, and you start using that more often. This is how it works.
The language you speak can have very lasting effects on you and how you perceive things. Its basically a "you are the company you keep" sort of thing. If the community you are able to communicate with (speaks your same language) is generally smarter, has particular ideals, culture, does things a certain way ... Then generally you will fall closer to their way of doing and seeing things.