During a linguistics conference in Tokyo he met and had a conversation with a young man named David Cain about the potential ability to read body language as a fluent primary language. Several years later the pair was reacquainted in Thailand where Cain showed him his daughter, Cassandra Cain, and her abilities to read body language as her primary language.
Lewis Friedman is a world-renowned professor in neuro-semiology and created a book titled; Secret Words: Private Vocabularies and Other Linguistic Esoterica.
Years later, during a case in Gotham city where he was called in to act as an expert in deciphering letters he was met by Cassandra Cain, now Batgirl, and assisted in her solving the case of The Doll Man.