Introduction and objectivesInadequate auditory feedback in prelingually deaf children alters the articulation of consonants and vowels.The purpose of this investigation was to compare vowel production in Spanish-speaking deaf children with cochlear implantation, and with hearing-aids with normal-hearing children by means of acoustic analysis of formant frequencies and vowel space. MethodsA total of 56 prelingually deaf children (25 with cochlear implants and 31 wearing hearing-aids) and 47 normal-hearing children participated. The first 2 formants (F1 and F2) of the five Spanish vowels were measured using Praat software. One-way analysis of variance (ANOVA) and post hoc Scheffé test were applied to analyze the differences between the 3 groups. The surface area of the vowel space was also calculated. ResultsThe mean value of F1 in all vowels was not significantly different between the 3 groups. For vowels /i/, /o/ and /u/, the mean value of F2 was significantly different between the 2 groups of deaf children and their normal-hearing peers. ConclusionBoth prelingually hearing-impaired groups tended toward subtle deviations in the articulation of vowels that could be analyzed using an objective acoustic analysis program.