Re: Extended Breastfeeding (edit)
Might depend on the child, assuming the parents are not neurotic. My opinion (while you wait for Mh's view) is that it's often the best, and/or the necessary thing, in many cultures. "Natural" would be that the baby is never presented with images and visions of all the western junk that's masquerading as food that a baby gets into...and s/he would brestfeed as long as s/he wishes. I think once they grow a set of teeth, it's probablly time to eat.
my son weaned himself at around nine months. I had nothing to do with it. It made good sense to me, and suited him. 'Nine months in, nine months out.' He was very deliberate about whatever he did, like he was studying everything intently, and became a master crawler -- he would do a lot of squats before he ever took an upright step and started walking. When he got upright and walked, he was already a 'pro' and could run up and downhill. Thankfully, he had a rather idyllic beginning, in secluded country air, able to pick raspberries as he willed.
edit:
I think if extended breast-feeding is being promoted more now, it's either because there's a recognition that it's the child's best protection (which the giants like Nestle have sought to deny and undermine for decades!), or,...well, the alternative is just plain negative: Sick mothers, passing their lowered immunity (all all drugs, etc) on to the children. Let's focus on the positive, instead. A vaccination-free infant, growing strong on mom's milk, and then naturally weaning her/himself...
amen.