Maybe it is because your mind gets cleared out (Sometimes Blank) when you get into your 70's, but my Spanish came back tonight, as it was after two years of speaking Spanish in Bolivia in 1970- 1972.I was even able to speak some Quechua with my young relative from Ecuador.
Then again, sometimes, it's hard to remember what I ate or what clothes I wore two days ago! I find my mind and memory to be a real mystery at times! For instance, for a long time I believed you could not change the past, but recently I realized that is not true. You can change the past by changing your perspective on it.