Yes, formal grammar instruction is optional. But it does accelerate things. I mean, it may depend on your goals. If you are focused on communicating, and don't

Yes, formal grammar instruction is optional. But it does accelerate things. I mean, it may depend on your goals. If you are focused on communicating, and don't actually intend on using the language efficiently and competently, then maybe formal grammar is a waste of time. Otherwise you need to have this information. You have a choice to get it in a systematic way or to decipher it on your own.