Google+ right from the beginning provided support for RTL (Right-To-Left) languages like arabic, hebrew and persian.
Google+ Hangout adds RTL (Right to Left) language support
However Google+ hangout lacked that RTL support and caused some inconvenience for those G+ users.
The good news is hangouts has now added RTL language (arabic, hebrew and persian) support and ready for use.
Google+ hangout in Hebrew
Google+ hangout in Arabic
To set your language preference, goto Google+ language settings page and set your preferred languages (refer image below)
Want to read posts written in a foreign language? There is a nice G+ translation plugin that makes it easy for you. Enjoy!