The importance of speech rehabilitation of edentulous patients arises from practical reasons and from clinical trials which showed that there is an alteration of physiological speech in patients with removable dental prosthesis (RDP). In this paper we have considered the prosthodontic importance of determining the closest speaking space while determining the vertical occlusal dimension as well as the impact of RDP occlusal plane and palatal plate on speech. The potential negative impact of the interrelations between the tongue, mouth and prosthetic teeth on phoneme production has been described bearing in mind that prosthesis placement is the most important factor of speech. The aftercare of a RDP patient includes monitoring of subjective and objective factors which impair physiological speech. Speech implications in RDP patients have been described by a functional relationship between the tongue and the palate and by computer speech analysis. The influence of RDP on speech can be evaluated by speech analysis and this can have a broader linguistic importance, e.g. for disgnathous patients. In this way, the influence of natural or prosthetic anatomical factors on speech can be evaluated with respect to other compensational mechanisms which sustain the physiological function of speech. In this paper we analyzed the importance of speech factors for the fabrication of RDP as well as the speech alterations which appear in patients with RDP.