The relations between parameters defined above are also described. Numerous methods of analysis and observation of the laryngeal functions during speech have been developed in recent years. Phonation comprises mechanical and aerodynamic phenomena. Direct observation of vocal fold movements is possible only visually, whereas in practice the aerodynamic excitation signal can be examined only indirectly. The latter method uses an additional signal carrying information about the phonatory process.
Most techniques are invasive and thus uncomfortable for a subject.
A detailed classification of techniques is given in Tab. 3 . Techniques for the evaluation of laryngeal behavior. The most straightforward technique is auditory evaluation of voice quality. Follow this link to find more about techniques of vocal folds observations.