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.
You will know when to stop breastfeeding because a baby who is well attached will stop feeding when he has had enough. He will usually push out the nipple â he may look sleepy or even drunk or he may be calm and look around. If he is still awake offer him the other breast. He may want some or none of it.