WordNet (r) 3.0 (2006):

speech organ
    n 1: any of the organs involved in speech production [syn:
         speech organ, vocal organ, organ of speech]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "speech organ":
   alveolar ridge, alveolus, apex, arytenoid cartilages, back, blade,
   dorsum, hard palate, larynx, lips, nasal cavity, oral cavity,
   palate, pharyngeal cavity, pharynx, soft palate, syrinx, teeth,
   teeth ridge, tip, tongue, velum, vocal chink, vocal cords,
   vocal folds, vocal processes, voice box