We report the results of four experiments conducted with German and French infants addressing the question of when infants determine the predominant pattern for bisyllabic words in their surrounding language. We presented German 6- and 4-month-olds and French 6-month-olds with trochaic or iambic bisyllabics. The German 6-month-olds showed a preference for the trochaic pattern, but not the German 4-month-olds nor the French 6-month-olds. However, French 6-month-olds were able to discriminate trochaic from iambic bisyllables. This suggests that the preference for the language predominant pattern of word stress arises between the ages of 4 and 6 months in German. In French, in which there is little if any accentuation at the lexical level, 6-month-olds do not show a preference for any stress pattern, but are sensitive to acoustic differences between trochaic and iambic bisyllables.