Thanks for all the information provided.
For non-experienced hires (like in your situation), offices usually require to speak their local language, at least up to some level (it's not black or white..). It's also important for yourself on office Fridays to not be left out from some information conversations and being really part of that office. Also, for local projects it's important to speak local language - even though official language might be English, you will never bond the same as in local language though.
(For experienced hires - if there is a need for a certain resource/skill-set in the respective office for staffing some projects - the language is less important ..).
The most secure way to get to on-site interviews is always to network your way into that, and have some consultant (the higher in the ranks, the better) forwarding your application to HR. Unless your application documents are a complete mess, with that route you surpass the first HR screening and get invited to on-site interviews directly. Oftenly this is easier said than done - but with Xing/Linked-In etc. you have good tools in your hand to do some research and try to find some connections, unless you anyway have some acquaintances "somewhere" around close to those firms you are targeting.
In respect to the real requirements, you can always give HR a call upfront just to find out if local language is an absolute requirement from their side as well. Don't by shy to call them on the phone, it's their job to service potential hires!
Hope that helps - if so, please give it a thumbs-up with the upvote button!