Can AmCharts display dates with non-English months / weekdays?

Yes.

You can use AmCharts.dayNames / monthNames / shortDayNames / shortMonthNames arrays to set them to whatever strings you need.

Here's how to translate long month names to German:

AmCharts.monthNames = [
  'Januar', 
  'Februar',
  'März',
  'April',
  'Mai',
  'Juni',
  'Juli',
  'August',
  'September',
  'Oktober',
  'November',
  'Dezember'];

Here's a related class reference page:

http://docs.amcharts.com/javascriptcharts/AmCharts