MANDAN etymology

[Koontz John E]

On Tue, 3 Aug 1999, Alan H. Hartley wrote:
> Alexander Henry the Younger (1809, _Journal_ (1992) 393) records
> "Saiwahtoukta" as the Assiniboine name for the Mandans. (Can anyone
> analyse it?) This name argues against an A. origin for the English name,
> at least in Henry's time.

I should mention that I think this name reminds of some of the variants
for Otoe, too.