Effects of parallel syntactic training in French plural spelling and German noun capitalization

French plural markers and German noun capitalization encode syntactic information. Both syntactic markers present the syntactic information needed reliably and saliently, and both are unrelated to phonology. A main difference between both is that French plural spelling is part of inflection morphology and encodes the plural morphemes in written French. German noun capitalization is not a morpheme or a grapheme, but an allograph licensed in a particular function of the sentence, the head of the NP. Although both are substantially different, studies have shown that syntactic training is effective at improving the spelling of these syntactic markers. The current study presents two intervention studies in Grade 4 (N = 176) to examine whether learners who become literate in German and French benefit from a syntactic training in French plural spelling and German noun capitalization. All participants were trained in both languages and tested at four test points. Instruction was provided through learner videos (10 × 10 minutes) shown in a classroom setting. In both languages, the main goal of the training was to raise awareness of the syntactic unit of the NP as well as the syntactic information encoded in spelling. The results show large, short-term and long-term effects of the French training. However, unlike in previous studies, no training effects were found in German when compared with the control group. The paper discusses the results with a focus on the detailed comparison of French plural spelling and German noun capitalization as well as the feedback of the participating teachers in order to provide hypothetical explanations of the mixed training results. The discussed findings have an impact on the conception of syntactic spelling, as well as its teaching and learning.