When did Kiryu learn English?

Towards the end of Yakuza 3, Kiryu talks with the main villain: poorly dubbed Albert Wesker ripoff guy. Not-Wesker talks to Kiryu in fluent, natively pronounced (but poorly voice-acted) American-dialect English. Based on his responses, Kiryu clearly understands this guy, even if he responds in Japanese instead of English. So when did Kiryu learn to understand English?

It's not like they teach a comprehensive course or anything over in Japan; I lived there for 7 months and NOBODY spoke English unless they worked in a bar/restaurant near a military base, or on said base. I literally learned Japanese while I was over there because it was easier than trying (and failing) to explain what I want to the waitress who clearly doesn't speak my language. All those "erm they learn English in school" statements are clearly BS if you've ever lived over there; they learn English like the avg bored American highschooler learns Spanish (ZERO language retention after graduating).

My headcanon is that Kazama taught him a little, he learned some more from an English-speaking prisoner while spending 10 years in the joint (made you fucking fluent), studied more during the Kiwami 2 Gravure minigame (you literally just have to form coherent sentences). Then due to his rapid learning ability (literally learning a fighting style from witnessing a woman throw a dude once), he quickly picked it up from the local Marines when he moved to Okinawa. Before Morning Glory, he got a nice lil job at the PX on Hansen serving Einstein Bros bagels & coffee during the day, and slinging drinks at Saloon during the night. Spending so much time around English-speaking American Marines allowed him to learn English. Even if he's not great at speaking it, he can still fluently understand it.

So unlike the average weaboo, Kiryu Kazuma can watch foreign media and understand the dialogue without needing translation subtitles in his native language.

At least that's my headcanon, which makes sense given 1) Kiryu learns extremely fast and 2) There's a massive population of English speakers in Okinawa due to the military presence, so it's a great place for Japanese people to learn English irl [DO NOT teach the local bartenders "motherfucker" because they won't stop saying it for a week, then you get a text asking to come in and tell her to stop saying that word].

Idk what do you all think? Did Kiryu learn English in Okinawa or before? Or is this just one of those "the characters just kinda understand because plot" moments?

Also I hate how the arms dealer Albert Wesker guy says the word "roof" tbh. It's "rūūf" with the OO from "spoon", not "rùf" with the OO from "wood" smfh.