We report two experiments that assessed the role of orthography in constraining subject-verb agreement in written (Experiment 1) and spoken (Experiment 2) French. We contrasted a condition in which the singular and plural forms of the subject head nouns were homophones but nonhomographs (e.g., chanson, song-S, vs. chansons, songs-P) with a condition in which the subject head nouns were homophones and homographs in their singular and plural forms (e.g., refus, refusal-S,P). An effect of the orthographic marking was found in written production but not in oral production. The results, together with our previous findings, suggest modalityspecific feedback effects during grammatical encoding: orthographic representations influence written production but morpho-phonological representations influence oral production.