In 2013, the French parliament legalized marriage between same-sex persons. One issue of debate was to define whether people were debating about “marriage for everybody” as claimed by the supporters of the law or about “homosexual marriage” as the opponents labeled it. This research aims to analyze the effects of social lexical markers (SLM) reflecting social groups of opinions elicit when embedded in a persuasive message. A first study showed that SLM are explicitly identified by people but only when embedded in a low-quality arguments persuasive message. SLM also increased identification certainty when they are concordant with arguments’ orientation. A second study demonstrated that, whatever the quality of argumentation, argument orientation guides both cognitive responses and attitude change. Furthermore, SLM reinforced effects of argumentation orientation when they are concordant with arguments orientation. These results are discussed in light of the elaboration likelihood model and intergroup processes.