Meaning seems at once the most obvious feature of language and the most obscure aspect to study. It is obvious because it is what we use language for—to communicate with each other, to convey 'what we mean' effectively. But the steps in understanding something said to us in a language in which we are fluent are so rapid, so transparent, that we have little conscious feel for the principles and knowledge which underlie this communicative ability.
Questions of 'semantics' are an important part of the study of linguistic structure. They encompass several different investigations: how each language provides words and idioms for fundamental concepts and ideas (lexical semantics), how the parts of a sentence are integrated into the basis for understanding its meaning (compositional semantics), and how our assessment of what someone means on a particular occasion depends not only on what is actually said but also on aspects of the context of its saying and an assessment of the information and beliefs we share with the speaker.