Interesting theory, but I think Mohammed claimed to be illiterate (it was "divine inspiration" that allowed him to read the text) and even if he could read, I doubt he could read Hebrew.
Mohammad as a professional trader on a major route generally used by Jewish traders probably had a good command of Hebrew, or he had access to a translator.
He certainly had plenty to say about the times he had occasion to meet with Jews. In fact, he had started out with the idea that he should reform Judaism.