Vocal folds auto-oscillation is the result of a fluidstructure-acoustic interaction within the larynx. Vocal folds structure changes are often associated with voice pathologies affecting voice professionals as well as the general public. Therefore, in this work, the influence of the vocal folds structure on the auto-oscillation is investigated. An experimental study of the influence of local vocal folds rigidification on the resulting auto-oscillation is presented. Silicone molded four-layer mechanical vocal folds replicas are used. The layers composition and elasticity properties reflect the multi-layer anatomical representation of a human vocal fold. A local rigidification within these vocal fold replicas is obtained by adding a stiff rectangular inclusion during the molding process. The position and orientation of the inclusion are varied in a way that the elasticity of the replica is affected. For each replica, the auto-oscillation characteristics are experimentally studied on the basis of pertinent physical quantities such as upstream pressure and vocal folds displacement.