Hey there! :)
The copy of bootstrap-datepicker that you provided only seems to contain the English translation, which is why trying to set the language isn't working right now. I did a bit of research, and the solution is actually quite simple. I'd be happy to discuss with you so that you can have the translation working as soon as possible.
As for the standard "about me" formalities, I've been using JavaScript both professionally and as a hobby most of my life, and I've been freelancing as an expert in JavaScript for quite some time now. By all means, feel free to check my profile for a few testimonials from past clients, as well as to get to know a bit more about me.
With that out of the way, I'd love to hear from you as soon as possible. Toss me a reply so we can get started right away! I look forward to working with you. :)