The study of the 2700 occurrences of phrase-terminal extension particles (e.g., tout ça ‘all that’, des affaires de même ‘things like that’) in two large corpora of Montréal French reveals that they are typically formed of some combination of a quantifier, a generic and a comparative, and that the particle is optionally prefaced by a connector (the conjunctions puis, et ‘and’, ou ‘or’). The 76 particle types (not counting minor variations) also include a good number of fixed forms (e.g., et cetera) often having an onomatopoeic aspect (e.g., patati patata). Extension particles can be characterized through prosodic, syntactic, and semantic criteria. The analysis bears on the sociodemographic conditioning of overall rates of particle use; of choices within the quantifier, generic, and comparative categories; and of preference for each of four major classes of particle: those containing a universal quantifier, those containing an existential quantifier, those consisting of just a generic and a comparative, and fixed forms. The discourse insertion of the four classes is also analyzed in terms of connector, type of discourse transition, the complexity of the term(s) semantically “extended” by the particle, and the discourse genre. The clearest result pertaining to overall rates of use is an age-grading effect, whereby speakers use fewer particles as they grow older. Within the components, women use more quantifiers than men, and both generics and comparatives are sharply stratified by social class and age. The reconstituted particles tend to favor certain co-occurrence patterns and avoid others more than could be predicted from the component distributions, consistent with a stylistic concord effect. As for the four classes of particle, it is the presence and nature of the connector that have the strongest effects, where puis contrasts with both ou and the null connector, while the complexity of the extended term distinguishes among the classes both by virtue of the number of terms and their syntactic complexity. As is predictable from functional considerations the sociodemographic factors do not contrast the two semantically most distinct classes, involving universal versus existential quantifiers. The linguistic validity of the four classes is confirmed by the fact that their quantitative conditioning is not predictable from the strong sociodemographic conditioning of their component elements, but rather reflects their differential suitability for various discourse functions.