English to Chinese (Simplified + Traditional).
Traditional Chinese means that the characters are traditional, instead of simplified which is used now in Mainland China. When learning Chinese it is for sure a good idea to learn the traditional form too, as some simplified substitute more than one traditional characters. Traditional characters are also a very important and beautiful part of the cultural heritage and it is best to learn them with the simplified forms.
My recommendation is to have both simplified and traditional versions on the screen in the Linguist.