In Znagui (1995), on investigation was made of the coarticulatory influence of lingual consonants differing in place of articulation (interdental /S, ©/. alveolar/s, z/, palatal /f, 3/, postpalatal /k/, uvular 1%, a, q/, pharyngeal /h, 1/ and pharyngealized /t\ s , d9, C / on the adjacent vowels /a, a:, i;, i:. u, u:/ in Modern Standard Arabic (MSA). Measurements were taken of the distance between the frequency of Fl and F2 in the vowel steady state. The results showed that two categories of vowels could be distinguished as a function of the distance between Fl and F2. The objective of the present study is to investigate the perceptual significance of this acoustico-phonetic classification. One question of interest is to see if native speakers of Arabic can discriminate between these categories of vowels.