"There is no one to take care of her."
Translation:Некому о ней заботиться.
The given sentence can also be translated as "Нет никого, кто мог бы о ней позаботиться", in which case никого is indeed the genitive case of никто. Некому, however, is the dative case form of the pronoun that has no nominative case. It is a convolution of the phrase "нет такого человека, кому [можно было бы поручить / захотелось бы]". Here are some examples of using other non-prepositional forms of this pronoun: некого спросить (=there's nobody to ask), её некем заменить (=there is no one who could replace her; literally: "her, there is no one with whom to replace"). If a preposition is required, the pronoun turns into a three-word phrase. Examples: не у кого занять = there's no one to borrow from; не от кого ждать помощи = there is no one to rely on for help (literally, "there is no one from whom to expect help"); не к кому пойти = there is no one to go to; не с кем поговорить = there is no one to speak with; не о ком вспомнить = there is no one to remember; etc. The dative form некому can either refer to the subject of the following infinitive, or to its indirect object, and, in some cases, the phrase can be ambiguous. For example, некому жаловаться may be understood as "there is no one who would complain" and as "there is no one to complain to".
Thank you very much for the quick and detailed reply! So некому is indeed dative, and I can understand why one would use некому in sentences like Ему некому подарить подарок since the negative predicate pronoun is the indirect object.
But I didn't understand why the negative predicate pronoun is dative in this particular sentence, because it is the subject. Is it safe to assume this type of pronoun takes the dative case by default, when it is the subject?
Yes, if, by 'subject' you mean the doer. It is advisable to avoid using "некому" with verbs that can have an indirect object in the dative, as this usage will result in ambiguity. For example, ״Там некому дарить подарки" can be interpreted as "There is nobody there to give presents" and as "There is nobody there to give presents to". By the way, in all negative pronouns starting with не, including the 'three-word' ones не is always stressed, whereas ни in negative pronouns is never stressed. Another important fact is that некто and нечто mean 'a certain person' and 'a certain thing', respectively, so they are not negative. For obvious reasons, некто only has the nominative case form. Нечто also has only one form which can be nominative or accusative, depending on the context. When we need to use 'one person' or 'one thing' in other cases, we just decline the phrases 'один человек' and 'одна вещь'. Некто is used before a name (a certain X), whereas нечто is normally used before an adjective (e.g. нечто невообразимое = something unthinkable). Это было нечто! = That was something!
It is not exactly obvious but pretty natural.
Their oblique forms would coincide with forms of некого and нечего, which have a completely different meaning and use. It would be fairly inconvenient.
Нечто and некто mean "a certain person", "a certain thing" (in narratives about the past некто is often used with the name of "some" person you imply you knew nothing about).
Некого and нечего, on the other hand, need no Nominative form because they are always used in impersonal sentences (sentences that lack a formal subject).
http://masterrussian.com/aa022401a.shtml The source is pretty good, except I spotted one inacuracy there: the prepositional case form of некого is wrongly illustrated with не с кем, which, although has a preposition, is an example of the instrumental case. (Prepositional is not the only case that allows using a preposition). Examples of the prepositional case include не о ком, не в ком and не на ком.
This sentence has no ambiguity.
The issue is, некого and нечего will take the Dative case if they take over the role of what would be the grammatical subject otherwise:
- Я её люблю. → Некому её любить.
- Чайник сломался. → Нечему было сломаться.
If you use a verb that can attach a Dative recipient, you have an ambiguity (usually resolved by context). Некого and нечего would naturally be Dative if they replaced something that was already Dative anyway.
- Я отправил сообщение. → Некому было отправить сообщение.
- Мы помогли Саше. → Нам некому было помочь.
In Russian, отправить "send" has 1) subject 2) object 3) recipient. Помочь "help" has a subject and a recipient. If you make некому-sentences with these verbs, it may not be immediately clear who некому refers to.