Fora do wiki ele diz:
Unlike the book, where they are devious, plan extensively, and speak at great length; the movie shows them as silent attackers in one scene only. This is due to multiple factors. The length of the movie was one, finding gorgeous Japanese identical twins who spoke English was another; The Saitos couldn't speak English.
Para reiterar: Os atores poderiam não falar inglês ! Por isso eles não tiveram uma participação no filme.