Family terminology in Inraj Sargaĺk is one of the parts that most certainly are a holdover from the substrate. In part, a strong reason to suspect that this system is conservative is its unusual traits.
First, comparing the most immediate family terminology, we find that the system of distinguishing siblings, uncles and aunts by age is not well-established in Inraj Sargaĺk. Thus simi signifies all male siblings, and tame all female siblings.
The Inraj family terminology with regards to offspring, aunts, uncles, grandparents is specific to generations in a cyclical manner. Thus, a given person was born during the time considered to be the time of generation 1. He is considered the ospa of his father, who belongs to generation 3. His son will not be his ospa, however, but his ərok.
The graph below has 'female siblings' to the left, male siblings to the right, and parent/descendant in the middle - with females to the left, males to the right. Thus, aunts' and uncles' side of the family are not distinguished. The graph is cyclical, i.e. going downward past "mile / ərok", you get "adan / mota" again, etc.
Thus, a person of the ərok generation will have a mota for grandfather, a motbor for great uncle, an ospa for father and an ospor for uncle, an adkas for great aunt, a diskes for aunt and dise for mother. A mota will have an ərok for dad, etc. In the unusual case where greater spans of generations have survived, the prefixes mar-/mer- and sul-/sil- signify 'old' or 'young' to distinguish the two, e.g. maradkas : 'an adkas of the older generation when two adkas generations coexist', a sildise is the younger person that could be termed dise.
The most immediate family terms - sister, brother, father, mother, son, daughter - are often the same as in regular Sargaĺk, but in religious contexts even those are replaced by the terms here. For even slightly more distant relatives - uncles, aunts, grandparents, grandchildren - these terms are the usual terms.