why would you use उनकी for both their and her? Shouldn't you use उनके for their, and उनकी for her???
उनकी only means "their", not "her". It's in feminine form because किताब is feminine.
Actually उनकी can have a meaning of all these - "her", "his" and "their"
why would you use उनकी for both their and her? Shouldn't you use उनके for their, and उनकी for her??
Given the right context इनकी, इनका, इनके, उनकी, उनका, and उनके can all mean her, his or their.
The sound clip for यह sounds more like यहा, which could be confusing for learners as it changes the meaning from "this is their book" to "here is their book"
The two sounds do sound somewhat similar, but यहाँ has a more nasal 'ahn' sound at the end, which gives it away. Also यहाँ doesn't often come at the beginning of the sentence (though it can). A more natural translation of "Here is their book" would be (I think) उनकी किताब यहाँ है।