The Collaborative International Dictionary of English v.0.48:

Palatalize \Pal"a*tal*ize\, v. t. (Phon.)
   To modify, as the tones of the voice, by means of the palate;
   especially: to pronounce a consonant with the tongue against
   the palate; as, to palatalize a letter or sound; to palatize.
   See palatalized.
   [1913 Webster + WordNet 1.5]

WordNet (r) 3.0 (2006):

palatalize
    v 1: pronounce a consonant with the tongue against the palate
         [syn: palatalize, palatalise]