Originally Posted by
Sharingan
Maybe they consider English to be a 'cool' language. If you listen to Japanese media, such as films, anime, games and music, you'll very often find English terms interspersed in the dialogue, even though the Japanese language undoubtedly has equivalent words for them.
One particular instance of this is in the (Japanese) dialogue of Metal Gear Solid 2, where Solid Snake is happily speaking Japanese, then suddenly inserts the word 'scoutu knifu' (= scout knife) in there. Hilarious.