Intensification can be expressed cross-linguistically by several morphological and syntactic constructions (among others, Kirschbaum 2002; Hoeksema 2011, 2012; Zeschel 2012; Rainer 2015). The language-specific preferences for particular types of intensification, and the competition between the learners’ L1 and L2 constructions (Ellis & Cadierno 2009), complicate the acquisition of intensifying constructions for second language learners. This study focuses on one specific case of such constructional competition, namely the expression of intensification in the interlanguage of French-speaking learners of Dutch or English. More specifically, we will address three research questions: (i) To what extent can we observe variation in the use of intensifying constructions between the native and learner language? (ii) Does more input provided through a Content and Language Integrated Learning (CLIL) approach lead to a more native-like acquisition of intensifying constructions? (iii) Does CLIL have a similar impact on the acquisition of each of these two languages? The data for this study come from a corpus of written productions of 5th graders (aged 16-17) in French-speaking Belgium, in CLIL and non-CLIL settings learning Dutch (CLIL n=132; non-CLIL n=100) or English (CLIL n=90; non-CLIL n=90) as a foreign language, and control groups of 63 native speakers of Dutch and 68 native speakers of English of about the same age . All instances of adjectival intensification observed in this corpus are subjected to a collostructional analysis, more particularly covarying collexeme analysis (Gries 2007), which expresses the degree of attraction/repulsion of an adjective to a particular intensifying construction in the form of pbin-values (Stefanowitsch and Gries 2003; Gries 2007; Ellis and Ferreira Junior 2009). The results are compared across the different speaker groups in order to identify constructional preferences. Preliminary analysis shows that intensifying compounds are significant collostructions in the L1 corpora, e.g. ...