Source : Webster's Revised Unabridged Dictionary (1913)

Bleat \Bleat\, v. i. [imp. & p. p. {Bleated}; p. pr. & vb. n.
   {Bleating}.] [OE. bleten, AS. bl?tan; akin to D. blaten,
   bleeten, OHG. bl[=a]zan, pl[=a]zan; prob. of imitative
   origin.]
   To make the noise of, or one like that of, a sheep; to cry
   like a sheep or calf.

         Then suddenly was heard along the main, To low the ox,
         to bleat the woolly train.               --Pope

         The ewe that will not hear her lamb when it baas, will
         never answer a calf when he bleats.      --Shak.

Bleat \Bleat\, n.
   A plaintive cry of, or like that of, a sheep.

         The bleat of fleecy sheep.               --Chapman's
                                                  Homer.

Source : WordNet®

bleat
     n : the sound of sheep or goats (or any sound resembling this)
     v 1: talk whiningly
     2: cry plaintively; "The lambs were bleating" [syn: {blate}, {blat},
         {baa}]