I can speak three languages and morse was similar to learn. From the first day of training they gave us sheet of paper with the alphabet and the morse translation and told us to memorize a couple of letters. Then they sent us outside to spend hours staring at a flashing lightbulb.
When you recognize a letter your writer (someone with a clipboard standing facing you and away from the light) would write it down, and when you didn't recognize the letter you said "MISS".
The first day was spent saying "MISS... MISS... MISS..." It was extremely frustrating, the same way being immersed in a new language can be. It felt useless... as if I would never get it. Every day we'd spend the morning staring at the light, and little by little we started to get more letters.
Once we mastered it (100%) they would turn up the speed and we'd be back to where we started... "MISS... MISS... ECHO... MIKE... MISS... MISSS..." until we perfected that speed and were moved up again.
It took about three months of daily practice to get up to the military's standard.
I catch myself years later spelling out words in morse in my head.