Content Warning: This section contains discussion of antisemitism, anti-gay bias, and the Holocaust. 

All of the major characters in Indecent are Jewish, and many of them speak Yiddish as their native language. When any character speaks their native language, they speak fluently, but otherwise, they have a noticeable accent and sometimes make grammatical errors. Most of the play is performed in English, though there are a few lines and short scenes in Yiddish (and Nakhmen says some lines in French, Spanish, and Chinese). When Sholem Asch is a young man, writing in Yiddish allows him to connect with Jewish people and make meaningful art about his culture, even if his writing is considered controversial. Yiddish is not universally celebrated in Europe, even when Sholem is young: Freida makes derisive comments about Yiddish and about Jewish people, foreshadowing the further challenges that the characters face when they get to America.

In New York City, there is a big enough Jewish audience to stage The God of Vengeance in Yiddish, but Yiddish theater is not prestigious. To create a prestigious play in America, it is essential to perform it in English so it has a chance to make it to Broadway.