Every language is a highly structured system that is nevertheless
subject to constant variation and change--because many of its parts
reflect cultural conventions, rather than unchanging natural logic.
L103 is an introduction to the systematicity as well as the
conventionality (and apparent arbitrariness) of Language in
general.  The topics covered therefore include the parts of language
(e.g., meanings, sentences, words, and sounds), the uses of language
(e.g., to facilitate conversation or to request information), and
the ways in which languages are acquired by children, processed by
adults (plus children), and varied or changed over time (by
virtually everyone).