The existence of wireless and mobile technology has provided opportunities to support learning regardless of the physical learning space. Thus for example, usage of mobile terminals such as smart PDA (personal digital assistant) in a learning system is very common phenomenon. Mobile devices can communicate with wireless mobile terminal and realize the intelligence exchange with its surroundings. Based on this current trend and the need to realize learning in a more dynamic environment, a LOCH (Language Learning Outside the Classroom) system named One Day Trip is developed to assist overseas students to learn Japanese in real life situations with the help of a PDA. This paper proposes the task assignment support function in the system to aid the teacher to give learners appropriate tasks in the learning environment.