Lewis & Short

balbūtĭo (-uttio), īre, v. n. and a. [balbus].

  1. I. Neutr., to stammer, stutter: balbutire est cum quādam linguae haesitatione et confusione trepidare, Non. p. 80, 13; Cels. 5, 26, 31: lingua, Cod. 15, 6, 22.
    Transf., of birds, not to sing clearly: merula hieme balbutit, Plin. 10, 29, 42, § 80.
    1. B. Trop., to speak upon something obscurely, not distinctly or not correctly: desinant balbutire (Academici), aperteque et clarā voce audeant dicere, Cic. Tusc. 5, 26, 75; id. Div. 1, 3, 5.
  2. II. Act., to stutter, stammer, or lisp out something: illum Balbutit Scaurum pravis fultum male talis, he, lisping or fondling, calls him Scaurus, Hor. S. 1, 3, 48.
    Trop., as above: Stoicus perpauca balbutiens, Cic. Ac. 2, 45, 137.