I've always been a synthesthete, although I didn't even know there was a word for what I experience and the (very) few people I told about it thought I was weird. I learned about it when I was in my 40s, and now find that it's relatively common in bipolar disorder.

I see numbers, letters, and words in colors, and I can "taste" colors as well. To someone whose wires aren't crossed this way, that makes NO sense, but to me it's as natural as breathing.