This research describes a method applied at a U.S. university in a third‐year Russian language course designed to facilitate Advanced and Superior second language writing proficiency through the forum of argumentation and debate. Participants had extensive informal language experience living in a Russian‐speaking country but comparatively little formal language instruction, especially with regard to writing. The authors quantitatively analyzed weekly position papers and ACTFL pre– and post–Written Proficiency Test compositions using prescribed complexity measures and compared them with qualitative ACTFL proficiency ratings. Preliminary findings underscore the value to both the writer and instructor of applying both quantitative and qualitative measures; they likewise point out challenges associated with teaching students whose language has become automatized, albeit oftentimes error‐full, in part owing to the nature of past language study.