Heritage Language Education at a Crossroads: A Systematic Review on Two Decades of Research in the UK (2004–2024)

Although heritage languages (HL) education has gained increasing recognition in UK multilingual contexts, research in this field remains fragmented. This article provides a systematic review of 86 empirical studies on HL education in the UK published between 2004 and 2024. A methodological review was also conducted to examine the range of research designs and analytic approaches employed. A synthesis of the identified studies generated four major themes: (1) publication and methodological trends, (2) outcomes of HL education (psychological, social, and educational), (3) key debates on HL education research (theoretical, conceptual, methodological, policy and pedagogical), (4) research gaps and future directions (theoretical, methodological and practical). Through a critical discussion of these themes, the review highlights five research directions: (1) moving beyond language maintenance towards supporting holistic development; (2) recognising HL as a contested and dynamic process of legitimation; (3) moving from rhetoric to sustainable system design; (4) adopting lifecourse perspectives; and (5) reframing participant voice as power. The review concludes by outlining a future research agenda that integrates ecological, interdisciplinary, and participatory perspectives to strengthen theoretical coherence, methodological rigour, and sustainable practice in HL education.