The ring, the wrestlers and the training
Start with dohyo, the sumo ring, and mawashi, the belt worn for wrestling. Rikishi refers to a sumo wrestler, while keiko refers to practice or training. These words give you a useful way to describe what you are seeing and to ask simple questions. You do not need to pronounce everything perfectly before attending. Listen to how your instructor and interpreter use the terms, and connect each word with the actual demonstration.
Recognise movement and technique words
Shiko is a fundamental sumo movement often recognised by its leg lifting and stamping action. Suriashi refers to sliding footwork. Kimarite means a winning technique: the Japan Sumo Association maintains an illustrated catalogue. Two examples are oshidashi, a push out, and yorikiri, a force out with close body contact. Treat these as labels to recognise while watching. Written descriptions are not a substitute for the instructor’s guidance on what to attempt in your own session.
Use a few words well
Basho is a tournament, and banzuke is the ranking list associated with professional sumo. Together with the terms above, these words help distinguish training, competition and the people involved. Before the session, choose two questions that interest you rather than trying to learn a long glossary. Afterwards, note the words you actually heard and the context in which they appeared. That small personal vocabulary will be easier to remember when you next watch a match or explore official sumo resources.