I think you are limited to what you can spell using the ASCII character set. I'm a single language white trash American, so I'm not familiar with Hebrew. But I've seen such words written in the ASCII character set, like "meshuga", "shibboleth" and so on. I grabbed these from http://en.wikipedia.org/wiki/List_of_English_words_of_Hebrew_origin so it's possible that these are not what you want...