The ability to speak well in public was considered a good character trait (Proverbs 21:23; Proverbs 25:15).1 In this context, it most likely refers to his poetic ability; he sings as he plays the harp. In recommending David to Saul the unnamed servant has drawn attention to David’s family background (a brave man and a warrior), and now he affirms that David knows how to sing and has handsome features.
18 L'un des serviteurs prit la parole, et dit: Voici, j'ai vu un fils d'Isaï, Bethléhémite, qui sait jouer; c'est aussi un homme fort et vaillant, un guerrier, parlant bien et d'une belle figure, et l'Eternel est avec lui.