"She reads a black book."
Translation:Ŝi legas nigran libron.
The accusative is a case that marks the direct object of a sentence; Most verbs shows a relationship between a subject that's acting over something directly (which will answer the questions what? whom? how many? by the verb) - that "something" is the direct object of that sentence.
- I like my mother (who do you like?)
- I have two dogs (how many dogs do you have?)
- I eat apples. (what do you eat)
In some languages, this feature of language (the direct object) is marked with a change in either adjectives, pronouns, nouns and articles - you call that the accusative case.
Modern English doesn't have an accusative case (Old English and Old Norse did have one though, as do Icelandic and Faroese, which retained many features from the latter), but you can still see its remnants on the object pronouns (me; you; him; her; us; them), which are also present in Norwegian (meg; deg; henne; oss; dem).
My Norwegian is not that advanced, but I do understand "Tusen takk" (and Google Translate filled me in on the rest)! You're welcome - I'll hopefully move into learning Norwegian more thoroughly once I become more fluent in Dutch, but I loved everything I've learned so far!
Good luck with your Esperanto studies - don't let the -n and the exceptions throw you off from learning it - If you have any other doubts, feel free to send me a message or to ask the community: we're all here to help one another :)
@Luis Domingos : Excellent explanation. But I am not sure that the question "how many" also requests accusative form.
At least, in French, we only consider "who?" and "what?" to look for accusative words.
(there is not change in the word spelling itself but the preterit used with the auxiliar "have" may change of form regarding the place of the accusative word.)
Can someone confirm how to use it in Esperanto? :)
Try this link. If it doesn't work, try using your regular keyboard to put the letter X after any character which needs a hat.