I had heard the word “only” spoken in English, but didn’t know how to spell it. At the same time, I had seen the word written, but thought it was pronounced “on-lie” — oddly enough, I had never heard anyone use “on-lie” in speech; I thought it was one of those words that exist but aren’t used very much, like “splendid” or “indubitably”.

I just remembered I also had trouble for so long with the English words “union” (pronounced like English “onion”) and “onion” (pronounced “onny-on” or “on-ion”).