Yeah, if you don't use it, you lose it, me too! I was getting better and better at it because I had a coworker who was deaf, and she was the one who taught me. I learned words we needed in our every day speech first, which is the best way to learn, instead of some foreign language textbook full of things you are never going to say. But I haven't lived in that same town where my friend is for years, and so I only get to use it sporadically now, like with that patient, or when I worked customer service maybe a couple of times.
The funny story is when I was a returns cashier, I saw that my coworker was doing the writing back and forth thing with a customer, so when I was done with my customer, I offered to come over and interpret. ...just as the two customers were signing to each other that my coworker was a bitch. I giggled, and they gasped, not sure if I understood naughty words or not (I do). I told them don't worry, I won't tell. And we finished the transaction. XD