Learn the other language in Virtual Reality Chat, also known as, "VR Chat".
Post your times. The times you can be on VR Chat. Post your English world. Post your Japanese world. Post your teacher ratings. Post your ability to teach either language.
Here are in depth explanations of the above.
Post your times. The times you can be on VR Chat. What are the hours you can be on? Daytime? Nighttime? What time zone? Weekdays? Weekends?
Post your English world. What world do you want to meet in for teach or learn English?
Post your Japanese world. What world do you want to meet in for teaching or learning Japanese?
Post your teacher ratings. Who are good teachers? They taught beginning English or Japanese well? They taught intermediate English or Japanese well? They had a lot of time available? They are particularly effective?
Post your ability to teach either language. Are you able to teach English to a toddler? Are you able to teach English to a child? Are you able to teach English to a teenager? How about Japanese? Who are you able to teach to?

Here is an explanation of me. I am available to play from 17:00 California time, United States Pacific Standard Time, to 6:30 California time. I am not sure what worlds I prefer, but I am willing to join other people's worlds. I don't have any teacher ratings yet. I can teach English to toddlers, children, and teenagers. I don't know how to teach any Japanese.