"custom or custom-made, made to order," of goods, as distinguished from ready-made, 1755, earlier bespoken (c.1600), pp. of bespeak, in a sense of "to speak for, to arrange beforehand," a sense attested in bespeak from 1580s. Now usually of tailored suits.
O.E. besprecan "speak about, speak against, complain," from be- + 'sprecan "to speak" (see speak). A common Germanic compound (cf. O.S. bisprecan, Du. bespreken, O.H.G. bisprehhan, Ger. besprechen); originally "to call out," it evolved a wide
range of meaning in English, including "speak up," "oppose," "request," "discuss, "arrange," and "to order (goods)" (1580s).
"The connection of the senses is very loose; some of them appear to have arisen quite independently of each other from different applications of BE- pref." [OED]