A new language joined Facebook's list of options this week: the Kansai dialect of Japanese.

Kansai, a region in west-central Japan centered around the cities of Osaka, Kyoto, and Kobe, is known for its distinct language and culture. Many comedians come from the Kansai area, making the dialect commonly associated with humor. The population of the Kansai area exceeds 20 million people, a little over 16% of the national total.

Changing...