Back when I played on Masamune in 1.23 XIV, they had a party finder system similar to 2.0's and even back then they had thr comments in all caps "JP ONLY."

As annoying as it sounds and by the way that most english speakers interpret it, it's actually just thr Japanese language they are looking for only. Alt tab to google translate or look up common phrases and use them. So long as you are familiar with whatever they are doing and not messing up or making a fool outta yourself, most wont care if you join. Just dont use Auto-Translate since thats a dead give away you are baka gaijin. :P

This has always been the nature since even XI days, as stated above.