The Collaborative International Dictionary of English v.0.48:

Melodize \Mel"o*dize\, v. t. [imp. & p. p. Melodized; p. pr. &
   vb. n. Melodizing.]
   To make melodious; to form into, or set to, melody.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Melodize \Mel"o*dize\, v. i.
   To make melody; to compose melodies; to harmonize.
   [1913 Webster]

WordNet (r) 3.0 (2006):

melodize
    v 1: supply a melody for [syn: melodize, melodise]