In this paper, the first results from a longitudinal study of speech production in French are presented for 9 patients who underwent vocal tract surgery, including partial or total glossectomy or pelvi-glossectomy and tongue reconstruction, or partial mandibulectomy. For each patient, two recordings were made of the acoustic speech signal, the first one a few days before surgery, and the second between 3 weeks and 12 months after surgery. The analysis of the data aimed at two main objectives. First we wanted to quantitatively assess the degree of speech production impairment induced by the surgery and to propose explanations in terms of articulation. Second, we were interested to observe and to understand how some of the subjects with a strong impairment were able to modify their speech production control strategies, in order to deal with the dramatic modifications of their oral cavity. Data analysis was based on formant patterns for the vowels, on Lisker and Abramson's VOT, and on temporal and spectral properties of the burst for the consonants. Speech production after surgery was evaluated on the basis of a comparison with the pre-surgery recording, which was considered as a reference describing the patients' speech production under normal condition. Special attention was paid to the patients who showed the largest postsurgery difficulties, in order to find the origins of their impairment and to study the strategy adopted to deal with this impairment.

Index Terms. Speech Production, Glossectomy, Speech Pathology, Speech Perturbation