Yes, I'll always remember the long time spent asking for the whereabouts of Ocean Drive, mispronounced by me because the correct pronunciation would require the word to be written as Oshean or maybe Oshan. It was 1995. I have had very few occasions to hear native speakers. A lot of people and I were figuring out plausible but incorrect pronunciations by applying the most usual pronunciation rules to the written words.
its just a soft c? other languages have that too. English has soft c's after i, e and y. They probably didn't teach you that rule. its true that most English speakers pronounce soft c's as a "sh" sound these days, but it wasn't always the case.
If it were just a soft C, then "ocean" would sound more like "oh-see-in" or "oce-yin". But it's also been palatalized to sound like "oshin" in typical pronunciation. People might not have understood them because they didn't know this.
