I pronounced Alcove as Aclove for years. At least I had some idea that it was a dent in a wall with things in it. Most of the time I just figured out the meaning by osmosis of context. I know there were a few I got horribly wrong, but details don't leap to mind. But I sure remember Aclove's pronunciation, because I still remember the confusion on everyone's faces when they finally had to call me out on it. :)