The current Thai translation cause some issues with Calendar widget. You could see the effect at http://thaibaht.wordpress.com. The Calendar format display different than it should be. I believe it is because the Thai translation is too long.
Not sure how WP and the calendar widget get the string for Month.
December in Thai is: ธันวาคม
Dec in Thai is: ธ.ค. or ธค.
But somehow the system use both ธ.ค._ธันวาคม_ตัวย่อ which probably too long for the calendar width.
Anyone could change this to use either full month name or abbreviation.