defines short month names for your locale. It is then used in month axis labels.
ganttChartControl.useShortMonthNames(true); ganttChartControl.setShortMonthNames(["Янв","Фев","Мар","Апр","Май","Июн","Июл","Авг","Сен","Окт","Ноя","Дек"]); ganttChartControl.create("htmlDiv1");