Traditional speech processing methods for laryngeal pathology assessment assume linear speech production, with measures derived f r om an estimated glottal ow waveform. They normally require the speaker to achieve complete glottal closure, which for many vocal fold pathologies c annot be a c c omplished. To address this, a nonlinear signal processing approach is proposed which employs a di erential Teager energy operator and the energy separation algorithm to obtain formant AM and FM modulations from bandpass ltered s p e e ch recordings. A new speech measure i s p r oposed b ased o n p arameterization of the autocorrelation envelop of the AM response. Using a cubic model of the autocorrelation envelop, a three dimensional space is formed to assess changes in speech quality. This approach is shown to achieve exemplary detection performance for a set of muscular tension dysphonias. Unlike ow characterization using numerical solutions of Navier Stokes equations, this method i s e xtremely computationally attractive, requiring only N logN +8 N multiplications and N square r o ots for N samples, and is therefore suitable for real time applications due to its computational simplicity. The new non-invasive method shows conclusively that a fast, e ective digital speech processing technique can be developed for vocal fold pathology assessment, without the need for (i) direct glottal ow estimation or (ii) complete glottal closure by the speaker. The proposed method also con rms that alternative nonlinear methods can begin to address the limitations of previous linear approaches for speech pathology assessment.