Why some japanese games have english words?

I started to play Castlevania dawn of sorrow some days ago. The game is japanese, but I know how to read Hiragana and Katakana.

But some ite’s names like the short knife (Idk how this is in japanese) are not in japanese. They are write in Katakana, and in this case of the knife, it sound like “shoto kunaifu”.

And in Zelda Ocarina of Time, some actions like attack are in english (“atakku”, I guess).

Why?

by PokemonTrainer1000