Yep; I'm the same. My reading (comprehension) vocabulary is much greater than written or spoken. I tend to use more expletives and slang in my normal speech. Also, I never write "uh" or "um" but I am guilty of speaking them. I'm sure Barney enjoys the conversation. Before my little dog Harry died, I talked to him constantly. He was quite the good little listener, and I miss him every day.
I have one built into my kindle, so when I am reading, I use the dictionary from that. Otherwise, I just do an online search for the word.
I almost embarrassed myself yet again. I ran across two words in the same article that I was sure were just made up for the sake of whatever - 'perfervidly' and 'infelicitously.' This time, instead of looking online, I checked my Webster's New World Dictionary. There they both were. Now I've got to figure a way to work them into everyday conversation. "It's a perfervid day for winter, isn't it?" "Yeah, Joe Biden is leading Trump in PA. That's infelicitous." I better not try it. I don't want to get beaten up by the locals.