Auto-translation dictionary addition(s).

[Laraul]

Reason I say "For English" on Japanese Input on Windows you have custom dictionary and people made FFXI, FFXIV dictionary which pulls out all in-game terms, items, recipe just by typing few words, kind of like how the Kaomoji Dictionary works for the face ☆-(ノﾟДﾟ)八(ﾟДﾟ )ノｲｴｰｲ　<-- this stuff works just by typing "kao" (Face)
So in the JP dictionary you can add words like ファイア (Faia) and as you type ファ you will have the option of ファイア but also also show the English Fire as option

You are referring to the Windows IME not the auto translator. The Auto Translator works the same way regardless which language you use.