"How to say Saturday in English" can be translated into several ways depending on the context. If you want to ask someone how to spell it, you can say "How do you spell Saturday in English?" or "Can you tell me how to write Saturday in English?". If you want to ask what day of the week it is, you can say "What day is it today?" and they will answer "It's Saturday". If you want to ask about activities that are typically done on Saturdays, you can say "What do people usually do on Saturdays?" and they might reply with things like "People often go to the movies, shopping, or spend time with family and friends".
I hope this helps! Let me know if you have any other questions.