12 They married within the clans of the descendants of Manasseh son of Joseph, and their inheritance remained in their father’s tribe and clan.

Read Numbers 36:12 Using Other Translations

And they were married into the families of the sons of Manasseh the son of Joseph, and their inheritance remained in the tribe of the family of their father.
They were married into the clans of the people of Manasseh the son of Joseph, and their inheritance remained in the tribe of their father's clan.
They married into the clans of Manasseh son of Joseph. Thus, their inheritance of land remained within their ancestral tribe.