Technically, The Red Turtle is a joint venture French/Japanese film. But that doesn't really matter beyond informing the art-style; it's a hybridization of Western animation and anime. The reason it doesn't matter what country it's from is because there isn't any dialogue in the movie. It's not a silent film, strictly speaking. There is a lot of sound, there just isn't any language. The sound design does add a great deal to the experience the film provides and the lack of language also allows the film to be universally accessible.