In my case learning Welsh as an adult started a few years ago with some frantic activity. I am sure many learners are familiar with the Post it notes on the fridge door, the lists of vocab etc
Sadly it did not stick and it seemed that all I could manage was to listen to Welsh being spoken and pick out a word now and again. Clearly that is a million miles from understanding and yet I was stuck with a stream of noise or repeating sentences or playing games with dice in class. In reality we mix and match depending on who we are with, the situation, what we want to say and so on. We change and chop but the books give patterns which are useful but there seems to be a disconnect from that to the understanding. I am told that comes later and in my case probably decades so.
So the different patterns are complex but I have rarely thought in English – ooh that is a conditional tense and now need to try to replicate that as I try to learn to speak Welsh