Etymology:alteration (influenced by Latin dulcis) of earlier addoulce, adoulce, from Middle French adoulcer, adoulcier, literally, to sweeten, from a-(from Latinad-) + doulce, douz sweet, from Latin dulcis — more at dulcet
Addulce — Ad*dulce , v. t. [Like F. adoucir; fr. L. ad. + dulcis sweet.] To sweeten; to soothe. [Obs.] Bacon. [1913 Webster] … The Collaborative International Dictionary of English
adulce — earlier f. addulce v. Obs. to sweeten … Useful english dictionary