[orm]

Yeah, to add to your comment, this link has some more detailed explanations regarding the wheel+axle combo: https://www.livescience.com/18808-invention-wheel.html

It is also worth pondering why wheel+axle was invented so late even in Eurasia (after bronze alloys were invented and adopted, only around 5.5 kya, many thousands of years after agriculture).

This fact has changed my perspective on how much infrastructure already must exist to enable large wheels that rotate smoothly around an axis. Knowing that, it is no longer shocking that one might make toy wheels, and never scale them up to large ones.

[ncmncm]

It has been demonstrated linguistically that the Proto-Indo-Europeans had oxcarts with solid wheels. (Spokes came later.) They are estimated to have spread out over all of Europe and southern Asia sometime around 6-9 thousand years ago. Most languages in those areas trace directly to theirs. English has brought back together numerous words from various other descendants of it.

Notable exceptions from the PIE family are semitic languages, and Hungarian, Basque, and Finnish.