Rapid Maxillary Expansion (RME) is an effective orthodontic treatment for increasing the transversal dimension of maxillary bone and therefore palatal volume. However, expansion of the palate can affect speech by altering the articulation points of the tongue and changing resonance by enlarging the oral cavity. We set out to compare the effect of two such devices on consonant and vowel sounds using a perceptive questionnaire and speech analysis software.