NSRange from Swift Range?

Problem: NSAttributedString takes an NSRange while I’m using a Swift String that uses Range

let text = "Long paragraph saying something goes here!"
let textRange = text.startIndex..<text.endIndex
let attributedString = NSMutableAttributedString(string: text)

text.enumerateSubstringsInRange(textRange, options: NSStringEnumerationOptions.ByWords, { (substring, substringRange, enclosingRange, stop) -> () in

    if (substring == "saying") {
        attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)
    }
})

Produces the following error:

error: ‘Range’ is not convertible to ‘NSRange’
attributedString.addAttribute(NSForegroundColorAttributeName, value: NSColor.redColor(), range: substringRange)