First day of the week option
I noticed DuoLingo takes Sunday as the first day of the week, however, in much of Europe (at least where I live) Monday is regarded as the first day of the week. It would be nice if we could choose in the settings which one applies to us.
"According to the international standard ISO 8601, Monday shall be the first day of the week ending with Sunday as the seventh day of the week. Although this is the international standard, countries such as the United States still have their calendars refer to Sunday as the start of the seven-day week." from http://www.timeanddate.com/calendar/days/
Why not use an international standard instead?