In continuous speech, a vocalic segment presents an evolution resulting mainly of coarticulation effects. The idea of a unique point in the vocalic space, interpretable in terms of speech production, is attractive for the identification method. However, assumption of existence and unicity of such a point in vocalic segments is contradicted by many observations. Consequently, an improvement of recognition rate is expected if the evolution within the segment is taken into account in the identification process. Therefore, we propose a vowel recognition experiment by pattern matching (ie location and identification) on a BDSON (1) data base, including about 1500 vowels, in order to compare the advantages of a global principle of identification (ie on the whole segment) with the advantages of its local counterpart (ie on selected frame(s)).