Whinge isn't a simple spelling variant of whine. Whinge and whine are actually entirely different words with separate histories. Whine traces to an Old English verb, hwinan, which means "to make a humming or whirring sound." When hwinan became whinen in Middle English, it meant "to wail distressfully"; whine didn't acquire its "complain" sense until the 16th century. Whinge, on the other hand, comes from a different Old English verb, hwinsian, which means "to wail or moan discontentedly." Whinge retains that original sense today, though nowadays it puts less emphasis on the sound of the complaining and more on the discontentment behind the complaint.