How to use speech synthesis in Hebrew ?

Hello all,

I'm helping a blind person to use his computer and he speaks Hebrew. I'm 
looking for him to find an Hebrew voice to read his language.

Are you aware of such voice and how to use it with Speech Dispatcher ?

I've found mbrola voices in Hebrew but those voices don't work through 
Speech Dispatcher because Espeak or Espeak NG don't map them.

I've tried this command to test (I'm sorry but I don't know Hebrew 
sentence):
> echo 'I do a test' | espeak-ng -v mb-hb1 --stdin --pho

And I obtain:
> Error: The specified espeak-ng voice does not exist.

Best regards,
Alex.