This paper investigates word order of clitics in L2 Slovak and the possible impact of cognitive factors on it. Based on data from learner corpus, the paper makes a first attempt at a more thorough inquiry of ordering patterns in the interlanguage of non-native speakers of Slovak to assess whether cognitive principles of contiguity, relevance, and verb-object bonding possibly have an effect on preferential clitics placement, irrespectively of L1. As proxies for cognitive effects on word order, linguistic and (psycho)linguistic predictors are used, such as proficiency level to consider the possible developmental patterns of word order competence and L1 language group of speakers (languages with clitics W-systems and C-systems within Slavic group). The dataset includes 1051 sentences with annotated erroneous placement of clitics from learner corpus errkorp-1.0 developed under the Slovak National Corpus. The data are further annotated manually with respect to relevant variables (type of clitic component, syntactic environment in which this component occurs, expected and actual distance of clitic component from matrix verb in terms of linear dependency segments and syntactic words, actual and expected position of clitic component on right or left periphery of the matrix verb, proficiency level according to CEFR and L1 language group of speakers).