A Peculiar Innovation in the Dagurib Branch: Verbal Body Part Prefixes

In the Dagurib branch of the ĆŊ family, a set of verbal prefixes have developed, mainly from words for body parts. In Dagurib itself, we have

yül-, yil-, yul- hand, arm
ülül-, ilil-, ulul- hand, arm (alternative form)
si-, su-, sü- face
or-, ir-, ür- upper torso
sal, säl-, sɛl- legs, leg, foot, feet
t'ob-, t'öb-, t'eg- head
lok'-, lök'-, lek'- back
kno-, knö-, kne- belly, lower torso
gim-, wüm-, wum- genitals
gimim-, wümüm-, wumum- genitals (alternative form)
k'ar-, k'är-, k'ɛr- ass, butt
ban-, bän-, bɛn- thighs
sol-, söl-, sel- shoulders, neck
ene-, ono-, önö- mind, cognition

Cognates to some of these may be found in Ćwarmin and Ŋʒädär. These are mandatory in some situations, optional in some situations and not permissible in some situations. The participant of the noun phrase that they belong to is also not entirely trivial, as they can indicate instrument, object, physical direction, and some more unusual things.

Basically, the participant whose body the prefix will be part of most generally is the argument that would have been marked with the absolutive in an ergative language. The exceptions are hand and genitals, whose short form follows a nominative-like distribution, and mind, whose referent depends on the register: when spoken to a superior, it will often be used as a prefix whenever the superior is the object. Otherwise, it will often be used to make a recipient the focus of the clause. In fact, all of these tend to mark focus of the noun to which they relate.

Those which follow the ergative pattern acquire a nominative pattern when the verb is marked with the passive voice, but may block the passive voice from promoting object to subject as well as demoting subject to oblique. 

With indirect objects, whether to parse something as being part of an indirect or direct object is often specific to combinations of prefix and lexeme.