We have a house in spain and I once had a partner who was fluent, and have spent a lot of time reading, listening to being around Spanish. My spanish-to-english vocab is pretty solid. I can understand almost everything said to me even our little town with its funny accent.

But when I open my mouth to reply… yikes!

Usage is exactly my problem. I visited a hardware store and asked for “paint for wood” because I needed some varnish. The shopkeeper literally fell about laughing. Apparently what I’d actually said was “I’d like some paint for the forest”.