Here's an example using an attributed string:
var myString1 = NSMutableAttributedString(string:"this is probably what you want")
let myString1Font1 = UIFont(name:"Helvetica", size:14.0)
let myString1Color1 = UIColor(red: 1.000000, green: 0.976471, blue: 0.349020, alpha: 1.000000)
let myString1Color2 = UIColor(red: 0.850980, green: 0.043137, blue: 0.000000, alpha: 1.000000)
let originalNSString = myString1.string as NSString
let myString1Range1 = originalNSString.rangeOfString("this is probably what you want")
var myString1ParaStyle1 = NSMutableParagraphStyle()
myString1ParaStyle1.alignment = NSTextAlignment.Natural
myString1ParaStyle1.baseWritingDirection = NSWritingDirection.Natural
myString1ParaStyle1.lineBreakMode = NSLineBreakMode.ByWordWrapping
myString1.addAttribute(NSParagraphStyleAttributeName, value:myString1ParaStyle1, range:myString1Range1)
myString1.addAttribute(NSBackgroundColorAttributeName, value:myString1Color1, range:myString1Range1)
myString1.addAttribute(NSFontAttributeName, value:myString1Font1!, range:myString1Range1)
myString1.addAttribute(NSForegroundColorAttributeName, value:myString1Color2, range:myString1Range1)