The word 'เมื่อไร (mʉ̂a rai)' in Thai language is used to inquire about the time of an event or occurrence, it is the equivalent to the English 'When' or 'At what time'. It is generally placed at the beginning of the sentence, but it can also be put at the end, based on the context. Reviewing and practicing this term in various sentence structures is key to understanding and correctly use this common Thai word.