Speaker voice characteristics are an important aspect of forensic phonetics. Previous studies have suggested that all the features present in the speech signals are not equally important for speaker discrimination, and it is well-known that subsets of phonemes are more informative than others. However , most of theses studies have concerned a whole group of speakers, without taking into account the speaker speci-ficities. This paper presents a framework for the selection of a subset of phonemes from the speech signal at the speaker level in order to capture the speaker variability in this selection process. We present the approach for the selection of the most discriminatory phonemes and a preliminary study have been performed on French reading speech database. At the global level, the most discriminatory phonemes are compared to previous studies. At the speaker level, we have examined the inter-speaker variability according to their most discriminatory phonemes. The experimental results verified the effectiveness of the proposed framework.