Abstract: This study presents the cepstral and spectral analysis of a speech signal produced by a woman affected by a tracheotomy, with and without phonation valve. The spectral analysis based on parametric method (Autoregressive AR) using the fourth order cumulant, these analyses are used to detect and compare the principals characteristics of the speech signal: pitches, the formants and the intensity (energy) of corresponding voiced sounds (example: vowel i and u). The first results appear promising, since it seems, after several experiments there is no deformation of the spectrum as one could have supposed at the beginning, however this pathology influenced the pitch value, in addition the phonation valve influenced the energy value.