This volume presents a synthesis of cognitive linguistic theory and research on first and second language acquistion, language processing, individual differences in linguistic knowledge, and on the role of multi-word chunks and low-level schemas in language production and comprehension. It highlights the tension between “linguists’ grammars”, which are strongly influenced by principles such as economy and elegance, and “speakers’ grammars”, which are often messy, less than fully general, and sometimes inconsistent, and argues that cognitive linguistics is an empirical science which combines study of real usage events and experiments which rigorously test specific hypotheses.