Complex sentence: The two of them interrogated every seaman on ship who replied in a language other than English annoying the two of them who eventually lost their temper with a Black seaman whom they did not believe was unable to speak English.
Split into simpler sentences: The two of them interrogated every seaman on ship and each replied in a foreign language. Bunk and Freamon eventually lost their temper with a Black seaman whom they did not believe was unable to speak English.