Dutch laat staan and French encore moins: Constructional effects Marking the twenty-fifth anniversary of Fillmore, Kay and O’Connor’s (FKO, 1988) seminal paper on construction grammar, this paper explores various non-compositional effects of the commonest expressions corresponding to let alone in Dutch and French: laat staan (lit. ‘let stand’) and encore moins (lit. ‘still less’), respectively, the latter alternating with the expression encore plus (lit. ‘still more’) in affirmative contexts: (1) a. I can’t walk let alone run. → nl: laat staan; fr: encore moins b. I struggle to walk let alone run. → nl: laat staan; fr: encore plus Drawing extensively on data systematically gathered from corpora (CGN, DPC, GlossaNet, Linguee, Valibel), the web, and sound recordings, we show that these expressions exhibit language-specific idiosyncrasies and must be stored along with detailed knowledge about (i) the syntactic properties of their possible grammatical environments, (ii) the semantico-pragmatic (including information-structural) effects they trigger at clause level and (iii) the prosody of the constituent they occur in. Syntactically, laat staan is often followed by the complementizer dat (‘that’) in spoken Dutch, even when there is no subordinating conjunction in the first conjunct, which renders difficult its analysis (provided by FKO for let alone) as a kind of coordinating conjunction. We further found support for Verhagen and Foolen’s (2003) and Janssen and Van der Leek’s (2009) observation that the phrase/clause preceding laat staan need not be explicitly or even implicitly negative, a possibility which also exists for let alone. Regarding interpretation, we question FKO’s suggestion (1988: 519) that the context then should provide a proposition whose truth the speaker denies or whose level of informativeness the speaker disagrees with. Evidence for non-compositional semantics was also found for French (et) encore moins, specifically in cases where it is used after jamais ...