"What language do your students speak?" missing language
Although Duolingo is available for Hebrew, when configuring the settings for a class for Hebrew speakers to learn English, the option "What language do your students speak?" does not display Hebrew, even though other Semitic languages (e.g. Arabic, Turkish) are displayed as options.
Although there is a Duolingo course teaching Hebrew to English speakers, there's no course teaching English to Hebrew speakers yet.
It isn't just a matter of setting the interface language, each course teaching one language to speakers of another has to be built individually. Have a look at the Incubator to see which courses have been built, and which are being built at the moment.