The linguistic environment of a bilingual child is by definition more diverse than that of monolinguals: there are two languages present in the child’s environment, and as a consequence the bilingual child hears less of each language when compared to the input received by a monolingual child (REF). Thus, any investigation of bilingual language performance should always carefully consider language exposure patterns. In the second talk, we will investigate the quantity and quality of input in each language in the two bilingual groups (Polish-Norwegian, Polish-English). With the use of the smartphone application, parents regularly provide information on the immediate linguistic environment of their children. Our measures will include input quantity per day, i.e. the amount of exposure in each language on a particular day, and input quality per week, i.e. the number of speakers of each language, the availability of learning materials, the amount of parent-child activities, e.g. playing, singing, book-reading/storytelling and watching TV in a particular week. With such information gathered on multiple days, we are able to closely track changes in input patterns in both languages. We will link the children’s language performance in both languages (the timing of first words and vocabulary growth) to the reported quantity and quality of language exposure as well as to social/ family variables. We will also compare the input patterns between Polish-Norwegian and Polish-English bilingual families. Potential differences between the two groups may stem from the fact that Polish parents living in Norway often do not speak Norwegian well, hence the language environment at home may stay monolingual (Polish), in contrast to Polish parents in the UK who tend to incorporate English as a home language in addition to Polish (Miękisz et al., 2017).