You can delete this thread if you like.

I deleted my cookies and now it seems to be fine. (couldn't find the individual cookie for this site).

default site language is English
how do you visit the site? From bookmarks? Check what is the address that you use to access the site, it case there is a ?l=fr at the end
Also, in your browser options you can check imcdb's cookies: maybe there is a cookie defining the language which is corrupted and so not overwritten when you change the language.

For the past couple of days, when I visit the site I often end up with the French language version instead of English. Any reason why?