Mayumi Oka is widely respected as a leader in Japanese language education. Over the course of her distinguished career, she has taught Japanese at several prestigious institutions, including the University of Michigan, Princeton University, and Columbia University. She served as Director of the Japanese Language Program at the University of Michigan from 2004 to 2020. She also taught in the MA program at the Middlebury School of Japanese at Middlebury College from 2021 to 2024.

She is also widely known as a co-author of the Tobira series, a widely used set of Japanese language textbooks for university learners, as well as A Bilingual Dictionary of English and Japanese Metaphors. She is also the sole author of Sokudoku no Nihongo (Rapid Reading Japanese).

In addition to her work as an author and program director, she taught Japanese language pedagogy at the University of Michigan for more than fifteen years, helping train many future Japanese language educators. Even after retiring and returning to Japan in 2022, she continues to contribute to the field through workshops and initiatives supporting Japanese language teaching.

Masao Oka worked for many years as a businessman in the United States. After returning to Japan, he founded the nonprofit organization Music Culture Network ”MIRAINE", which supports children’s musical development. He currently serves as its chairperson.