The text has to be the same colour throughout the song. So if you want to have a different colour for Swedish and English, you could create a background with alternate stripes - see here:
http://tbn0.google.com/images?q=tbn:46q ... -sonsh.gifThe stripes would match the alternate lines of Swedish and English.
Then red here would have English words and the white Swedish ones. Or you could just have the top half in one colour and the bottom in another.
You can use a picture editor to create the colour rectangles and adjust their size, though you need to know which font and point size to work to otherwise the text may not appear on the correct part of the background.
You also need someone who is colour blind to check they can read it!!