Abstrakt
In Present-Day English, nearly functions as an approximator downtoner meaning 'almost, all but, virtually,' as do earlier variants based on the same root-nigh, nighly, near, next (to)-though more rarely and in more restricted contexts. Nigh functions as an approximator downtoner in Old and Middle English.
When near displaces nigh, nigh is retained as a downtoner with lexical adjectives expressing negative semantic prosody. Near is used as a downtoner in later Middle and Early Modern English.
However, degree adjunct uses are not well attested, thus pointing to incomplete grammaticalization. During the eighteenth century, the new -ly form (nearly) takes over the innovative downtoner function and the old form (near) is retained in the original locative sense, with some remnant downtoner uses.
Next (to) grammaticalizes as a downtoner, but proceeds only to the degree modifier stage and involves a high degree of idiomaticization, thus suggesting incipient grammaticalization. As spatial adverbs, nigh/near/next (to)/nearly represent one of the well-known sources for the grammaticalization of degree adverbs.
However, these forms seem to follow a pathway where the degree modifier use (adjective/participle modifier) precedes the degree adjunct use (verb modifier), contrary to the reverse pathway postulated for other degree adverbs.
