The Collaborative International Dictionary of English v.0.48:

Vocalization \Vo`cal*i*za"tion\, n.
   1. The act of vocalizing, or the state of being vocalized.
      [1913 Webster]

   2. The formation and utterance of vocal sounds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vocalization
    n 1: the sound made by the vibration of vocal folds modified by
         the resonance of the vocal tract; "a singer takes good care
         of his voice"; "the giraffe cannot make any vocalizations"
         [syn: voice, vocalization, vocalisation, vocalism,
         phonation, vox]
    2: the use of uttered sounds for auditory communication [syn:
       utterance, vocalization]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "vocalization":
   articulation, attack, bel canto, bravura, choral singing,
   coloratura, croon, crooning, delivery, diction, enunciation,
   folk singing, hum, humming, intonation, lyricism, mouth, mouthing,
   operatic singing, phonation, pronunciation, scat, scat singing,
   singing, sol-fa, sol-fa exercise, solfeggio, solmization, song,
   sounding, speaking, speech, tonic sol-fa, utterance, verbalization,
   vocal music, voice, voicing, warbling, yodel, yodeling