The whole knotty problem of deciding who is a native speaker (Muttersprachler) of the target language, and whether a translator can have two native languages and how to tell, is neatly sliced through in an advertisement for a patent translator to translate mainly into English in the Süddeutsche Zeitung:
bq. The translation department in our Munich office is seeking a qualified TRANSLATOR with English to mother tongue standard to start as soon as possible. …
bq. We are looking for a translator with a careful and conscientious working manner who enjoys a challenge.
bq. … we are offering you an attractive and responsible position as part of an international team.
I wonder how you test ‘mother tongue standard’.
(found on the pt group at Yahoo, thanks to Silke)