"My daughter is not sad."
Translation:Chan eil an nighean agam brònach.
It is highly complicated as far as people are concerned. As far as I am concerned, you should use mo for blood relations ('inalienable' things in the grammar books - that means things that are not a matter of choice - you cannot choose who your daughter or mother is but you can choose who your wife is). It has nothing to do with whether something is a possession - your master, your servant, your friends are all agam. Mo has in practice been extended to close family members, including pets, girlfriends, boyfriends etc.
But it is gradually extending, probably under the influence of English.
But then, on top of that, there has apparently been some confusion in respect of some family members and, in particular, because people say mo nighean for 'my girlfriend', because of the need to stress the closeness of the relationship, some people end up saying an nighean agam for 'my daughter' to distinguish. See https://forum.duolingo.com/comment/36086652?comment_id=37680332
So all in all it's a mess.
I originally lang syne learned duilich as "sorry", so tha mi duilich = I'm sorry rather than I'm sad, so maybe when it means sorry it has to have that underlying idea of regret or apology, rather than just unhappiness. Don't know for sure, but the drop-downs, I surmise, offer all the possibilities of meaning, whether appropriate in the circumstances or not. Maybe...
Historically it would have been
- mo nighean 'my daughter'
- mo mhac 'my son'
as blood relations are considered inalienable. That is the relationship cannot be changed. My daughter cannot suddenly become somebody else's daughter instead, any more than my shadow can suddenly become someone else's. But wives, husbands, boyfriends, girlfriends are the opposite. These relationships exist only because someone has made a decision. These are alienable relationships,
- an nighean agam 'my girl(friend)'
- am balach agam 'my boy(friend)'
(Note there are no gender-specific words that mean only 'girlfriend' or 'boyfriend'. I have simply given examples of words you might use.)
There are a couple of things you can never do
- You can never use agam in the vocative – when you are addressing someone. So you would have to say mo nighean when addressing her. Thus there is a song that contain mo nighean donn but also songs addressed to males.
- You can never use mo predicatively. That is, there is no Gaelic equivalent of mo that means 'mine'. If you were discussing whose mother someone was, you would have to say tha i agamsa 'she is mine'.
But the rules are not always stuck to. I have put a line to separate what is agreed from what is not agreed. There is a lot of confusion caused by
- The two last points I made above.
- Mo is often used to give a sense of intimacy. Mo nighean sounds like a much closer relationship than an nighean agam, so you might well use it for your girlfriend.
- The mo structure is much closer to the English, and this leads to people often using mo where agam would be historically correct. This then leads to people being told they are wrong and hypercorrecting to agam.
- You will often see claims that the rules have been reversed for females. From my experience there is absolutely no evidence to support this as a generalization applying to all dialects and registers, although I think it is true in some specific dialects. Further, there is no way to explain this swap without being extremely sexist and non-PC. Although I do not have direct evidence, I would be extremely surprised if they teach this sexist version in schools.
The net result is a total shambles, not just amongst learners but amongst native speakers as well. In this situation I think it is completely unjustified to mark someone as wrong because they are not giving the version that seems right to the question writer. It causes a lot of stress and confusion, and is not really worth learning anyway as it such a moving target.
BTW, it's am mac agam, as it's easier to say.