Aims and objectives/purpose/research question:We propose a model that captures general patterns in bilingual language processing, based on empirical evidence elicited in a variety of experimental studies. We begin by considering what linguistic outputs are logically possible when bilingual speakers communicate based on the typological features of two languages in the bilingual mind. Our aim is to explain why some outputs are more frequent or more likely than others in bilingual language use. Design/methodology/approach: Our empirically derived multi-factor model combines insights from various empirical studies of different bilingual populations and it includes a variety of methodologies and approaches, such as lexical categorisation, lexical priming, syntactic priming, event verbalisation and memory, historical language change, grammaticality judgments and observational reports. Data and analysis: We critically discuss both lexical and syntactic processing data, as well as data that reflect bilingual type differences and different communicative situations (i.e. who the bilingual speakers are talking to and for what purpose). Crucially, we explain when the relevant factors collaborate and when they compete. Originality: There are three main reasons why this paper can be deemed original: 1) it offers a unified model for understanding bilingual language processing that is not focused on a single factor or a single linguistic level, as has most often been the case in the past; 2) it brings together the study of bilingualism from both psycholinguistic and sociolinguistic perspectives and in a unifying fashion, which is rare in the literature; and 3) it creates a platform for testing numerous predictions that are not dependent on any one theory. Significance/implications: This new model opens up new avenues for research into bilingual language processing for all types of bilingual speakers and in different communicative situations. It captures and explains the variety of outputs in bilingual communication and enables us to make predictions about communicative outcomes.