Jean-Frédéric jeanfrederic.wiki@gmail.com writes:
See https://toolserver.org/~erfgoed/api/api.php : srcountry & srlang are the parameters you are looking for.
Thanks! I tested the lang parameter:
http://wlmmap.herokuapp.com/?lang=fr
(Sorry for the french-centric test.)
(Is "french-centric" an indexical pleonasm?)