Book excerpt: COST Action IS0804 “Language Impairment in a Multilingual Society: Linguistic Patterns and the Road to Assessment” aimed to profile bilingual specific language impairment (biSLI) by establishing a network for research on the linguistic and cognitive abilities of bilingual children with SLI across different migrant communities. A battery of tools for Language Impairment Testing in Multilingual Settings (LITMUS) was designed within the Action to achieve these aims, including the Parental Bilingual Questionnaire, the Sentence Repetition Task, the Crosslinguistic Lexical Tasks, the Multilingual Assessment Instrument for Narratives, and two nonword repetition tasks that are not language-specific. The chapters in this volume present research on one or more of the LITMUS tasks in bilingual children with typical language development and on use of the LITMUS testing battery for identifying possible language impairment. The work presented here will be of interest for researchers and clinicians alike, and have profound impact in our understanding of bilingual language development and impairment.