The paper focuses on Dynamic Assessment (DA), one of the diagnostic approaches used in the differential diagnosis of bilingual children who may present with communication disorders. The author provides a comprehensive overview of the theoretical foundations of DA, situating them within their historical and methodological context. The paper also presents the main subtypes of Dynamic Assessment, including the test–teach–retest model and gradual prompting and testing limits, along with examples of their practical application. Furthermore, the author relates the concept of DA to research on bilingualism and attempts to link the core assumptions of Dynamic Assessment with the speech-language diagnostic model proposed by Cieszyńska, as well as with conclusions drawn from the author’s own clinical practice.