Language is a code or collection of symbols, letters or words with different meanings attached to them. Example the word Dictionary is translated into the "book of words and there meanings". Who thought of that meaning with that word? Who knows, but that is what we relate the two together.
Semantics means the study of the way humans use language to evoke meaning in others. For example, "I said you are crazy". How many different ways can we say that and how many meanings could it have? That is why we have people studying language and how it transform.
Words are arbitrary. The meanings of each word are given by what we claim it is to mean. We can have the word "dog" as the word for a two legged mammal that speaks if everyone agrees on that meaning and communicates it that way. Each person talks, listens and thinks in a unique language that contain slight variables of it's agreed upon meaning.
Languages are shaped by our culture, country, gender, experiences, age and other factors. The meanings of words can also vary by which context we communicate the words.
We use language in unusual ways; communication can be difficult when people do not follow the so called language rules. Because of our culture, or our back grounds we change the meaning of a word to fit our culture or the times. Personal decisions dictate the choice of words and the structuring of them.
When speaking in a language we may not say it the exact way we write it on paper. We may have grammatical errors when we speak. Sometimes when we speak to each other we may Metatalk. Metatalk means we say something to our buddies and mean something different. For example "lets have lunch" generally...