The electrochemical interface between Ag(lll) single crystal and NaF + NaOH electrolytes at various pH values has been studied using cyclic voltammetry and in situ Raman spectroscopy. Submonolayer oxidation starts well below bulk silver oxide formation at potential about -0.6 V vs. Hg/HgO electrode at pH 11. Two potential-dependent Raman bands nu(1) at 540 to 560 cm(-1) and nu(2) at 803 to 819 cm(-1) in basic NaF electrolytes are attributed to Ag-OH stretching and AgO-H bending vibrations of electrochemisorbed hydroxide species. Strong isotope effect is observed in D2O solutions, nu(2) being shifted to values of 550 to 570 cm(-1). Fluoride stabilizes the adsorption of hydroxide species. A multistep scheme is proposed that describes the mechanism of formation of hydroxide/oxide species at the considered silver-electrode surface.