This cross-linguistic comparison of metalinguistic development in French and English examines early ability to manipulate derivational suffixes in oral language games as a function of chronological age, receptive vocabulary,and year of schooling. Data from judgment and production tasks are presented for children aged between 5 and 8 years in their first, second, or third school year in the United Kingdom and France. The results suggest that metamorphological development is accelerated in French relative to English. The French advantage encompasses knowledge of a broader range of suffixes and a markedly greater facility for generalizing morphological knowledge to novel contexts. These findings are interpreted in relation to the word formation systems of English and French, and the educational context in each country.