Language demonstrates structure while also showing considerable variation at all levels: languages differ from one another while still being shaped by the same principles; utterances within a language differ from one another while exhibiting the same structural patterns; languages change over time, [...]
This is a textbook right in the thick of current interest in morphology. It proposes principles to predict properties previously considered arbitrary and brings together the psychological and the diachronic to explain the recurrent properties of morphological systems in terms of the processes that c[...]