Definitely normal, and I agree that forgetting words is the most annoying. I constantly forget words that I use quite commonly, like the word adaptor, which I needed for the Christmas tree lights. Couldn't remember it for the life of me in the electrical shop. I had to resort to hand motions and "the thingy that connects the two-pin plug to the three-pin socket". Sometimes when I forget a word I just say the word "bananas" but only with my family because other people tend to look at me strangely.