This study investigated attention control in tasks involving the processing of relational terms (more highly grammaticized linguistic stimuli: spatial prepositions) and non-relational terms (less highly grammaticized lexical stimuli: nouns) in a first (L1) and second language (L2). Participants were adult bilinguals with greater proficiency in their L1 (English) than in their L2 (French) as determined by self-report and performance on a speeded word classification task. Attention control was operationalized in terms of shift costs obtained in an alternating runs experimental design (Rogers and Monsell, 1995). As hypothesized from consideration of the attention-directing functions of language, participants displayed significantly greater shift costs (lower attention control) for relational terms when performing in the L2 as compared to the L1, but no difference in shift costs for non-relational terms between the two languages. The results are discussed from a cognitive linguistic perspective and in relation to second language proficiency development. (Contains 1 footnote.)