Origin of thalweg. German Talweg, Thalweg : Tal, Thal, valley (from Middle High German tal, from Old High German) + Weg, way (from Middle High German wec, weg, from Old High German weg; see wegh- in Indo-European roots).
Besides as Sandra said the natural age of weaning is older than 2 and the WHO advises breastfeeding for a minimum of 2 years. It is not ridiculous that your son wants milk at 22 months. I fed my oldest child until 2.5 and am still feeding my 18 month old and plan to keep going as long as I can.
Weaning: When and how to stop breastfeeding. Weaning can be simple or a struggle, depending on your circumstances and how attached your child is to breastfeeding. Get advice on how to wean, when to know if it's time to start weaning, and how to address problems that might be pressuring you to give up breastfeeding. Also, get the scoop on introducing cow's milk to your child.