Definition of localisms:
(n) :
(uncountable) Attachment to a particular local place; feelings or policies which emphasize local phenomena.
(n) :
(countable, uncountable, linguistics) A linguistic feature that is unique to a locality.
(n) :
(uncountable, linguistics) The belief that language functions are localized to various parts of the brain.
(n) :
(uncountable, linguistics) An approach to understanding expressions in terms of position and movement (sometimes abstract, e.g. one who is hungry is in a notional "space" of hunger).