Patrick Bartley considers both jazz and Japanese his second languages. The American saxophonist, known for bright bebop solos over J-pop tunes, also believes fluency doesn’t require being native.

“You need to get closer to a culture to replicate its sounds. It influences how authentically you can play,” Bartley, 32, says over coffee at a cafe near Ikebukuro Station in Tokyo.

As leader of J-Music Ensemble, a jazz-fusion band specializing in instrumental covers of Japanese music, he approaches the language as a musician does a new genre — with an ear for subtle mannerisms. Miss the inflections and you lag and come off stilted, he explains. “Same as the blues.”