2 days ago I went to a convenience store and I noticed that the staff wasn't Japanese but more South Asian.
I've never lived in Japan myself but I've been visiting occasionally on and off since 1998 when I first went, so I've noticed a lot of changes over the years.
To my surprise, the staff did not speak Japanese and did not speak English either, and he tried ordering the Japanese customers around and none of them understood him.
Shouting at customers "LINE PLEASE! LINE!" Even in an English speaking country this poor level of communication would not be acceptable anywhere.
With the multiple aisles available he couldn't describe where he wanted the queue and how he wanted it, and he simply caused frustration and confusion.
A: This is not how you talk to customers (or anyone), it's very disrespectful, especially in a country that prides itself on treating customers with dignity and respect.
B: If you can't even form a single sentence using more than two words, in the main language or the secondary language that the country recognises, perhaps you should not be working in a job that requires verbal customer service.
I understand that everybody's situation in life is different, but if you are lucky enough to be accepted and welcome in any country, then the least you can do is make the effort to learn the language of that country.
If you are going to live in Japan or any country, then please respect the country, its citizens, its laws, culture and regulations.