I did some research out of curiosity. Using the API console, I wasn’t able to get any tweets in Hebrew unless I included lang=he in the query. This is interesting because the response is often coming back as lang=en, but querying lang=en returns nothing as does leaving it blank.
Anyway, try connecting to the stream with lang=he and see what happens.
(Update: now the search API is returning Hebrew tweets when the language is not set. It is still not returning tweets when lang=en though. Very interesting.)