The plugin supports i18n for the month and weekday names and the weekStart option. The default is English (“en”); other available translations are available in the js/locales/ directory, simply include your desired locale after the plugin. To add more languages, simply add a key to $.fn.datepicker.dates, before calling .datepicker(). Example

$.fn.datepicker.dates['en'] = {
    days: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
    daysShort: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"],
    daysMin: ["Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"],
    months: ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"],
    monthsShort: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"],
    today: "Today",
    clear: "Clear",
    format: "mm/dd/yyyy",
    titleFormat: "MM yyyy", /* Leverages same syntax as 'format' */
    weekStart: 0

Right-to-left languages may also include rtl: true to make the calendar display appropriately.

If your browser (or those of your users) is displaying characters wrong, chances are the browser is loading the javascript file with a non-unicode encoding. Simply add charset="UTF-8" to your script tag:

<script src="bootstrap-datepicker.XX.js" charset="UTF-8"></script>
    language: 'XX'