1) If you don't know how to pronounce the word, chances are you didn't learn it. Reading a word is not synonymous with learning the word. Almost everyone has heard of quantum mechanics. Almost no one learns it, ergo even less people understand it. 2) People who learn on their own, who are self taught, are called autodidacts (/ˌôtōˈdīˌdakt/ or auto-die-dakt). An autodidact will rarely mispronounce words, because they learned what it meant and how to use it properly. 3) At least you're reading.

I remember yesterday during one of my seminars, I came across the word "preponderant". I know what it means, but stuttered like mad pronouncing it in front of my students. #literaryproblems

I know what you mean. I read a lot and I pronounce long words in my head, so when I use them in real life it frequently comes out wrong.

There are actually YouTubers who make videos dedicated to the pronunciation of words. That could be something to look into OP.

So you didn't really learn them, you just read them?

Yes; however, learning new words will eventually exponentially increase your vocabulary conscientiously.

I play so many word games that I know all of the 2 letter words and probably around 90% of three letter words, but I have no idea what a lot of them mean. Qi, xi, xu...all I know is they score me lots of points! :)

I got you OP. I grew up reading more than talking and I am still finding words I thought I pronounced right are totally wrong. My family makes fun of me constantly for it. Good luck!

Introvert nerd problems. You know the word, you know what it means but you've never used it out side of reading or typing so you have no idea how it's pronounced.

More common than you might think, OP. fortunately for folks like us google now has audible pronunciation aids.