The study of language maintenance and language shift is concerned with
the relationship between change or stability in habitual language use,
on the one hand, and ongoing psychological, social or cultural processes,
on the other hand, when populations differing in language are in contact
with each other. That languages (or language variants) SOMETIMES replace
each other, among SOME speakers, particularly in CERTAIN types
or domains of language behavior, under SOME conditions of intergroup
contact, has long aroused curiosity and comment (46).2
However, it is
only in quite recent years that this topic has been recognized as a field
of systematic inquiry among professional students of language behavior.