Heritage language acquisition is the study of how individuals, typically growing up in a dominant language environment, acquire and develop a language spoken in their family or community of origin. As an interdisciplinary research field, it investigates the linguistic features, developmental pathways, and sociolinguistic factors influencing the acquisition, maintenance, and potential attrition of these languages. Key areas of focus include the unique grammatical and phonetic properties of heritage varieties, the cognitive processes involved in their use, and the impact of familial, educational, and community support on proficiency and intergenerational transmission.