It seems like a recent problem.

When I am in French, the content of the page is often a mix between English and French texts.

From IRC:

is there a request (www, ws, xml, json, etc.) that could return MB localised string(s) ?
so that we could (dynamocally) use the same terminology in user scripts than in MB's all languages
Hey... i am loading http://musicbrainz.org/artist/89ad4ac3-39f7-470e-963a-56509c546377 in french and half the page is french and the other is english...
halves were swapped at previous get
menu is always saying i'm in french
now *show more...* link in french, the tabs in english, the sidebar top in french, bottom in english
the wikipedia extract in french
was
now 100% french
maybe it's no big deal... i got language mix only for maybe less than 1 minute
(after having switched)
(language mix) actually the language mix is still going on after minutes