>Kanto = Kahn-toh
Same pronunciation as in Japanese
>Johto = Joh-to
Sort of like the Japanaese pronunciation of Kyoto, from which Johto takes a lot of inspiration.
>Hoenn = Ho-enn
Seems pretty straightforward, not sure how else you could say it.
>Sinnoh = Shin-oh
Blame Hepburn romanization for EN pronouncing Sinnoh as "sin-oh" when it's clearly meant to mean something else. Some fucking gaijin from the 1800s thought he knew what he was doing and now we have to pay for it.
>Unova = You-nova
Take the Un from United States and nova/new because it's based on New York.
>Kalos = Kah-lowse
It's the same as its Japanese name (Ka ro su), so there's really only one way it's supposed to be pronounced.
>Alola = Ah-lo-la
Same as in JP, and very clearly meant to be a play on Aloha and said the same way.
>Galar = Ga-lar
Like with Kalos, it's the same name in JP (Ga ra ru), so only one way.
>Paldea = Paul-day-ah
Yet again, it's the same in JP (Pa ru de a). They really gave up on naming the regions after Gen 5.