Based on the assumption that language is auditorily based and phonemes are auditorily perceived elements, this paper proposes a microlinguistic contrastive analysis of the vowel and consonant systems in English, French and Modern Greek. Consequently, the point of the discussion will be the three types of physical reality of these languages (articulatory, acoustic, auditory) and the functional difference in each language. This paper will also examine the implicational value of the notions of 'transfer' and 'interference' as a source for further experimental studies into the predictability of the English, French and Greek learner's difficulties and their bidirectional pedagogical potentiality: language teaching and interpreting.