Are assembly languages untyped?
Assembly language is normally untyped, in the sense that there is no type-checking.  Adding type-checking is a non-trivial research challenge (hence the papers you see).  Papers on typed assembly language should explain the motivation.  One application is that they can be used to support proof-carrying code, which can be used to securely execute untrusted code.  Another potential application is to support formal verification.  But I suggest reading some of the key papers to see what they say about the applications and motivation for typed assembly language.

You can find other papers yourself by doing a literature search -- see https://crypto.stackexchange.com/q/8316/351.