Why did they misspell Zebes as “Zebeth” at the beginning of Metroid?
It’s a translation thing. The Japanese have no “th” sound, so they replace it with an “s” sound when saying words they borrow from English. (For example, saying “Thank you” in English is sort of popular in Japan, and it comes out “sankyuu.”) The original Japanese version is “Zebesu” (u’s are often silent in Japanese). Because it’s a made-up word, they didn’t really know how to translate it to English, so they just picked “Zebeth” when they were converting the game (since it’s made-up, one is pretty much as good as the other). Unfortunately, whoever wrote the English-language manual picked “Zebes,” and that’s the one that stuck, so the intro of Metroid comes across as a typo. The “th”/”s” mix-up is pretty common when translating between Japanese and English, and it’s also the reason you’ll often see the name of Final Fantasy VII’s lovely flower girl written both as Aeris and Aerith.