A 302 HTTP response status code is appropriate for your use (language redirection). Moreover, the 300-class status codes do not indicate an error unlike 400-class status codes, which indicate a client error, and the 500-class status codes, which indicate a server error.
A 303 status code may be even better, but for interoperability reasons, 302 is well-understood by all Web browsers. See W3C's "HTTP/1.1: Status Code Definitions" for more information.