Recent studies on the phraseological aspect of languages, and as a consequence of the fact that they are frozen, have been redirected to highlight the centrality of this aspect in the description of languages. Far from being limited to marginal language phenomena, as has often been considered in grammatical and linguistic traditions, phraseology is at the very heart of the functioning of language systems. Already retained by precursors (Ch. Bally (1909) and Sechehaye (1921)) as a fundamental process ensuring the balance of the general economy of languages alongside combinatorial freedom (Mr Gross 1981, G. Gross 1996), phraseology is currently an essential element in the study of languages, making the lexicon a point where the glossary intersects prosody, morphology, syntax, semantic and pragmatic (Mel’CUK 2011 and 2013), whether general or specialised. The result of this change of perspective is a number of theoretical and applied questions: Is polylexicality, being a defining element of fixed sequences, covered by syntax (the internal combinatorial of fixed syntagms) or lexical morphology? Does the variation in fixed sequences, which relate either to the existence of several variants of the sequences or to the restructuring permitted by certain sequences, call into question the freezing of these sequences (cf. Anscombre 2012)? Would it be one of the essential processes in the grammaticalisation of syntactical tools (cf. P.-A. Buvet 2012); Where is the collocational phenomenon in relation to freezing? Does it fall within the scope of the freezing of schems or constructions? The share of textual phraseological coverage in general and specialised speeches? The share of culture? How can polylexical sequences be automatically recognised?