When we were planning our trip to Canada last year I thought it might be useful to relearn French as they speak it where we went. I did it at school, but just never got to grips with other languages. I failed at German too, but then I lived there for a couple of years and I still speak it fairly well. I think a major factor in learning is your attitude. If you want to learn something or need to learn it then you may do better. Just having to do it with no real goal is not inspiring.
Today I achieved a 365 day streak. That is actually not technically a year as we had an extra day in February, but I will take it. My cousin has a streak of over 1300 days!
I find the Duolingo app convenient. I often do some lessons whilst sitting with our foster cat, although she tends to climb all over me. I feel I am learning a fair bit, but might not feel that confident speaking it for real. I probably need some situation where I have to make conversation. I at least feel that I have learnt a lot of words and have some idea about how the language works. English, French and German have some things in common, but they each use different sentence structures.
I have yet to pay for Duolingo, so I have to put up with the ads apart from when they give me a few free days in the premium mode. I do not worry too much about their leagues as they serve no real purpose.
Part of the reason I am doing this is as a mental exercise. We need to use our brains to stay sharp. Mind you, my work is all about solving problems, so that might be enough. I still do some extra tasks such as Wordle, Connections and Framed. Connections is like the Wall on Only Connect. This is a very early edition of that when they used Greek letters rather than Egyptian hieroglyphs. We do like that show. It is tough and so very rewarding when you get an answer.
Making music is a different sort of mental exercise. I find drumming challenging as it means coordinating my limbs in various ways. You have to train them.
What is your preferred mental exercise?