Task-based language teaching (TBLT) focuses on using meaningful tasks and authentic materials to encourage language use. It originated in the 1950s and was popularized by Prabhu in India. A task is an activity with a specific outcome, like preparing a meal or solving a problem. TBLT has advantages like developing all language skills through meaningful use, but disadvantages include the difficulty of assessment and lack of focus on accuracy. The roles of both teacher and students differ from traditional methods, with the teacher selecting and sequencing tasks and students collaborating in groups.