The “optional infinitive” phenomenon, i.e. the existence of an early developmental phase in which children show a strong preference for using bare non-finite verb forms, has been the subject of many studies and much controversy. The aim of this study is to assess the role of distributional characteristics of the input for children’s early production of bare infinitives in two languages, German and French. For this purpose, three different input variables are investigated: the frequency, informativeness and salience of infinitives in child-directed speech. Results show that salience is the best predictor for the distribution of bare infinitives in the very early phase of development. Furthermore, lexical effects of individual verb forms on the patterning of bare infinitives in child speech are found which further support the constructivist idea that bare infinitives reflect the child’s learning of verb forms from compound finite verb constructions in the input.