mid-15c., "with respect to space or place," from local (adj.) + -ly (2). From 1803 as "with regard to a particular place or region."
Entries linking to locally
local adj.
late 14c., "pertaining to position," originally medical: "confined to a particular part of the body;" from Old French local "local" (13c.) and directly from Late Latin localis "pertaining to a place," from Latin locus "a place, spot" (see locus).
The meaning "limited to a particular place" is from c. 1500. Local color is from 1721, originally a term in painting; the meaning "anything picturesque" is from c. 1900. Local option (1868, American English) is from the prohibition movement: "the right of a community to vote on whether to allow the sale of intoxicating liquor there." Local talent "attractive women thereabouts" is from 1947 in UK slang; earlier it was used in reference to entertainment acts in shows, radio broadcast, etc.
Thus, with the local talent, we have many factors which help "sell" is in quantities far beyond what the commercial market would carry. Pride in children, interest in relatives and friends, and pride in locality all give impetus to the development of home talent. [Horace Boies Hawthorn, "The Sociology of Rural Life," 1926]
-ly 2
common adverbial suffix, forming from adjectives adverbs signifying "in a manner denoted by" the adjective, Middle English, from Old English -lice, from Proto-Germanic *-liko- (cognates: Old Frisian -like, Old Saxon -liko, Dutch -lijk, Old High German -licho, German -lich, Old Norse -liga, Gothic -leiko); see -ly (1). Cognate with lich, and identical with like (adj.).
Weekley notes as "curious" that Germanic uses a word essentially meaning "body" for the adverbial formation, while Romanic uses one meaning "mind" (as in French constamment from Latin constanti mente). The modern English form emerged in late Middle English, probably from influence of Old Norse -liga.