The Collaborative International Dictionary of English v.0.48:

Speckle \Spec"kle\, v. t. [imp. & p. p. Speckled; p. pr. & vb.
   n. Speckling.]
   To mark with small spots of a different color from that of
   the rest of the surface; to variegate with spots of a
   different color from the ground or surface.
   [1913 Webster]