JapanTaxi app introduced support for a few new languages. It now supports English, Simplified Chinese, Traditional Chinese, and Korean in addition to Japanese.
https://japantaxi.co.jp/news/cat-app...01/13/app.html

iOS https://itunes.apple.com/us/app/japa...481647073?mt=8
Android https://play.google.com/store/apps/d...data.japantaxi

Oddly (or rather not at all unusual for Japan) comments state the Android version requires a Japanese mobile number. My guess is also not a 050 IP Phone.