with the proper tongue to palate contact required for normal speech sound production. This article will briefly review the impact that rapid palatal expanders have on speech sound production and development in children and early adolescents who had such an orthodontic intervention. The introductory report includes a brief illustration about sound categories (consonants and vowels), sound analysis, and overview of rapid palatal expanders before reviewing the impact of palatal expanders on speech sound production. Sound categories and speech analysisSpeech production is controlled and regulated by over 100 muscles distributed through the chest, abdomen, head and neck. The creation of speech production involves three main functional systems: Respiratory, laryngeal, and supra-laryngeal. Spoken word in its original form is generated by air pressure variations [2]. Air flows from the larynx to the supra-laryngeal system and is acted on by one of the moving structures called articulators [3].Sounds in American English could be grouped into two categories: Consonants and vowels. Consonants are differentiated from vowels based on the extent to which the articulators cause airway constriction. That results in much more consonant articulation defects than vowels [4]. The consonant articulation is categorized into three basic dimensions, according to Bloodstein: Place, manner, and voice [4].