The aim of the present study was to evaluate the validity of combining two non invasive diagnostic approaches, (photorhinorheometry and sonography) in order study phonatory pathology in subjects suffering from velopharyngeal insufficiency (VPI). Twenty-six patients with nasal air escape during phonation and/or hyperrhinophonia due to to VPI were evaluated employing both methods. Phonorhinorheometry permitted air escape through the nasal cavities during phonation to be evaluated. Compartmentalization of the pharyngeal and nasal resonators during phonation was measured through MCF (maximal consonantic flow) values and MCV (mean consonantic volume), both normalized to the intensity of sound emission during the consonatic phases of speech. Sonography gave information concerning the phonema of resonance and articulation: a modification of the method, which also permitted sound production through an electroacoustic transductor kept in contact with the prelaryngeal skin, was made. This reduced intrinsic noise and increased dynamic modulations of the resonators of the vocal tract. Comparison between sonographic recordings obtained through a standard microphone and skin transducer permitted evaluation of influence of the vocal tract above the glottis on the phonatory process. In particular, recordings had by skin transducers showed a wider amplitude display and a better identification of vocal attack. Phonorhinorheometry and sonography are useful objective and non-invasive tools in evaluating phonatory pathology in patients suffering from VPI and in monitoring therapeutic approaches.