I would wager that you have heard it, but it didn't register in your brain. People often perceive others' speech as subconsciously more similar to their own than it actually is. I've been rewatching a lot of movies that I watched as a kid and people who I used to perceive as speaking in similar accents to mine but with unique voices actually turn out to have accents that are very different to mine. I didn't used to know pronouncing words like "cot" differently from "caught" was a thing at all, and now it's all I could hear when I rewatched Oliver and Company for the first time in like fifteen years.