The correlation between form and content is presented in linguistics by the language-speech dichotomy. Phonetics represents the speech (or the plane of expression) and phonology represents the language (or the plane of content). The operational unit of phonetics is the sound and the operational unit of phonology is the phoneme. The speech sounds (and the language phonemes) can be classified in terms of articulation (vowels, consonants and nasal vowels specific of French that include both vocalic and consonantal features) and structurally (single and compound units). According to the latter classification, there are units that can be regarded as compound phonetic sequences (CPS). Among researchers there is no consensus on the phonetic nature and phonological status of such units. Some of them regard CPS as monophonemic units, while others view these phenomena as phonetic sequences of simple sounds. The CPS occurrence values in French at the level of phonological inventory aim at the equal number ensuring a balanced correlation between the two categories of CPS, the dynamics of total and average values, of those of the extremes and amplitude. The graphic features of the CPS in the French language are that there are 2 units each of which has 2 modalities of graphical representation. As for other units each of them has a single graphical representation modality.