appreciate v.

word-forming element expressing direction toward or in addition to, from Latin ad "to, toward" in space or time; "with regard to, in relation to," as a prefix, sometimes merely emphatic, from PIE root *ad- "to, near, at."

Simplified to a- before sc-, sp- and st-; modified to ac- before many consonants and then re-spelled af-, ag-, al-, etc., in conformity with the following consonant (as in affection, aggression). Also compare ap- (1).

In Old French, reduced to a- in all cases (an evolution already underway in Merovingian Latin), but French refashioned its written forms on the Latin model in 14c., and English did likewise 15c. in words it had picked up from Old French. In many cases pronunciation followed the shift.

Over-correction at the end of the Middle Ages in French and then English "restored" the -d- or a doubled consonant to some words that never had it (accursed, afford). The process went further in England than in France (where the vernacular sometimes resisted the pedantic), resulting in English adjourn, advance, address, advertisement (Modern French ajourner, avancer, adresser, avertissement). In modern word-formation sometimes ad- and ab- are regarded as opposites, but this was not in classical Latin.

c. 1200, pris, "non-monetary value, worth; praise," later "recompense, prize, reward," also "sum or amount of money which a seller asks or obtains for goods in market" (mid-13c.), from Old French pris "price, value, wages, reward," also "honor, fame, praise, prize" (Modern French prix), from Late Latin precium, from Latin pretium "reward, prize, value, worth" (from PIE *pret-yo-, suffixed form of *pret-, extended form of root *per- (5) "to traffic in, to sell").

Praise, price, and prize began to diverge in Old French, with praise emerging in Middle English by early 14c. and prize, with the -z- spelling, evident by late 1500s. Having shed the extra Old French and Middle English senses, price again has the ancient sense of the Latin original. To set (or put) a price on someone, "offer a reward for capture" is from 1766.