Go read the Philosophical Investigations by Ludwig Wittgenstein. Most of what I say here arises from my understanding of what he says there.
A way of acting in the world, combined with humans' nature as language-users, gives rise to a way of speaking. Words, phrases, and so on, thus gain their meaning from the way of life from which they arise. To make some set of sounds is to say something because of how those sounds fit into a way of speaking. As there are various ways of being in the world, so there are various ways of speaking. A musician can say things which are meaningless to a mechanic, and vice-versa.
Call a way of acting or being in the world a "way of life." Call a way of speaking, i.e., a language with its characteristic usage, a "language game." These are phrasings from Wittgenstein.
If we imagine a language game, then there must be some ways of acting which go with it. If there are particular words in the language game, then there must be some actions, events, items, etc., which go with them. These words might refer to quite particular parts of a life: "my left hand," or be vague: "toy." Differences between words might be quite clear: "hat," "mitten," or vague: "jacket," "coat."
Things wind up having a kind of grammar, just as the words do. A sentence like "Colorless green ideas sleep furiously" it is grammatically correct as far as the sort of words they are, but when I say that a colorless thing cannot also be green, I am saying something about what I here calling the grammar of those words or concepts. That is, it is a comment about the way our words are allowed to go together. I am also making a grammatical statement of this sort when I tell you that an idea, itself, can't be green, even if it can be of something which is green.
When we want to know the meaning of a word or phrase, then, we are asking about how it is used in the language game. How is it used? What kind of life, or part of a life of what kind, is indicated when this word is used in this manner? A word may refer to a variety of things, some by analogy to others. The vagueness of a word is like the vagueness of a last name, thus Wittgenstein speaks of a "family resemblance" between the meanings of a word. How is go fish like chess, other than both being called a "game"? How are "football" and "soccer ball" alike, other than being confused for one another in writing by some people and both being called a "ball"? We might be able to see some connection between the two, or not, but this does not invalidate our use of the word "ball" or "game" for very different things.
As language is not fully a language apart from the practices which go with it, so the practices of people have meaning. My actions communicate. We read each others body language all the time, and this is a kind of communication. We can say of someone that it would be wrong to call them happy, and we justify it by observations about them. This is what is meant by using a word wrongly. Someone might tell us that, when they call someone happy, they mean that the person has taken to locking themselves in their room for long periods of time. We would say that they do not mean by "happy" what we mean by it, but that, if that is what they mean, then the person--who we would not call happy--is happy. This is a confusion caused by the person using a word in a way that is not recognized in our language game. Thus, they use it wrong, but it would be right if the language game were set up differently--and so they think it is.
We learn to communicate with others better, then, by learning the nuances of how they use the language. Their language game is set up slightly differently from ours, in every case. The mechanic, on hearing the musician speak of tones and fifths and quarter steps, might say "it's all Greek to me," and vice-versa. If the musician were to learn how to play music, though, then he would eventually learn how those words are used in that language game. Even between those in a similar discipline, there might be differences in how they use the language. We can imagine discussing what color to call something, or what we mean when we call someone our friend. Even more obviously, and at the same time more often overlooked, we might differ in what we call a "good day" at a very basic level. Is a day good if you were happy for most of it? If you were productive? If you got to spend most of it in bed? If you were unhappy for most of it, but felt by the end that it was for the best? Might you call a day bad if you spent it laughing and smiling at things which won't matter by the end of the week?