A brief and very interesting book, and certainly artifact of its time. Speaking of Indians was written during WWII, and was clearly written for a non-Native audience, and describes the church as the central institution of modern Dakota life. Some of the passages might be jarring to the modern reader--for example, her referring to descriptive Dakota names as a potential "handicap to progress" due to white people's ridicule, and suggesting they be removed in favor of names that would allow easier assimilation into white America at large.
That said, the sections introducing Dakota kinship roles and community life were wonderful, and really helped to lay the groundwork for Deloria's arguments regarding what she views as Dakota progress (and why she believes it has been slower than it could have been). I wasn't acquainted with the extensiveness of the web of kinship, the generosity and collective care involved. It really makes me view the early interactions between Dakota people and the settlers on their land from an entirely different angle, realizing the immense differences between what the Dakota and the white settler societies viewed as being "civilized" -- and the the clashing nature of what each expected from relationships with the other as a result. I'll be thinking about this book for a long time.