I have been studying Esperanto in my free time for a few weeks now, using Kurso de Esperanto, and I am understanding quite a lot of it. But I can't seem to understand when to use the accusative case(-n ending), and it's holding me back.

Do you know of any workbooks, exercises, programs, etc. that can review this in detail? I have already used the exercises on Lernu!, but there aren't enough of them and I still don't get it.

*Edit - Thank you all very much for your replies, and taking time to help me. I have never received this many replies to a question in such a short amount of time anywhere else on the internet, and so I feel welcomed into the Esperanto community. I plan to take time through the next week to study a bit more intensively, and begin posting sentences for review on the forums.

There are three cases in which the noun or pronoun takes n. (i.). When it is the direct object of the verb, as Mi vidis lin, I saw him. (ii.). To show direction, as Li iris en la ĝardenon, He went into the garden. (iii.). When the preposition is left out. This is usually done in the case of dates and expressions signifying duration of time, as Georgo Vaŝington estis naskita la dudek-duan de Februaro de la jaro mil sepcent tridek du, George Washington was born the 22nd of February, 1732. Vi restos tie ĉi la tutan vivon (dum la tuta vivo), You will remain here your (the) whole life.


- Lesson 26, The Esperanto Teacher

Detailed

(1) N is added to every noun and pronoun, other than the subject, unless it has a preposition before it. (Lesson five, The Esperanto Teacher)

(2) When we want the adverb to show "direction towards" any place, time, etc., either actually or figuratively, n is added, as Li alkuris hejmen, He ran home. Ili levis unu manon supren, They raised one hand upwards. Antaŭen! Forward! (n is also added to nouns to show direction towards. Li eniris en la domon, He entered into the house). (Lesson 12, The Esperanto Teacher)

(3) When we cannot decide which is the correct preposition to use in any case, we may use "je," the only preposition which has no special meaning of its own, or the preposition may be left out altogether, and "n" added to the noun or pronoun, provided that no want of clearness ensue (see Lesson 27), as Mi ridas pro lia naiveco, or, Mi ridas je lia naiveco, or, Mi ridas lian naivecon, I laugh at his simplicity.

When we wish to express "motion towards" something, and the preposition does not of itself express it, n is added to the noun or pronoun, as in the case of adverbs (see Lesson 12), Li estas en la domo, He is in the house; but, Li iras en la domon, He is going into the house. (Lesson 26, The Esperanto Teacher)

(4) En means in, inside; when n is added to the noun which it precedes, it means into, as Kie vi estas? Mi estas en la domo. Kien vi iras? Mi iras en la ĝardenon. Where are you? I am in the house. Where are you going? I am going into the garden. Malamiko venis en nian landon, An enemy came into our country. (Lesson 27, The Esperanto Teacher)

Demian:
(1) N is added to every noun and pronoun, other than the subject, unless it has a preposition before it. (Lesson five, The Esperanto Teacher)

Err, the predicative is without -n, too, even an object predicative:
Li estas mia amiko. - Mi nomas lin mia amiko.

Velleos:I have been studying Esperanto in my free time for a few weeks now, using Kurso de Esperanto, and I am understanding quite a lot of it. But I can't seem to understand when to use the accusative case(-n ending), and it's holding me back.

Do you know of any workbooks, exercises, programs, etc. that can review this in detail? I have already used the exercises on Lernu!, but there aren't enough of them and I still don't get it.

It might take you a while to get used to this. Keep at it. Analysing sentences you find in books, copying them, reciting them several times, visualising the 'actor' and the 'acted upon' of each sentence is a good way to practice. The good news is that if you get it wrong in conversation, people usually understand you anyway and at most you'll get a well-meant correction. (If you do get corrected, just repeat the sentence correctly as per directions, unless you didn't understand something, then move on!)

A few weeks really isn't that much time.

The rule of thumb I tell beginners who struggle is this - if your sentence is structured noun1-verb-noun2, and if the verb isn't a form of "esti" and doesn't have the -iĝ- ending, then noun2 needs the -n ending. And no -n after a preposition, ever.

Those two rules are an oversimplification of when to use -n. If you were to follow the rules strictly, always, you would almost always be using -n correctly, and you'd be wrong in a few cases. BUT they are helpful rules for establishing correct patterns of speech for the most common use of -n, to show the object.

In my opinion, that's the easiest way to learn -n. To learn its core usage first (as an object) and to get yourself habitually using it. And then when you feel comfortable with that, start worrying about the other details - -n to show time, -n to show distance, -n to show movement in a direction etc. These other usages of -n are optional in the sense that there is usually another correct way to say the expression (such as with a preposition) that doesn't involve -n.

-n is a complex topic and if you are trying to learn every single detail first, and then apply it, I think you drown in the details and find it a lot harder, than if you focus on the core usage first, and then the peripheral usages second.

Also, don't limit yourself to exercises. If you want more practice, write up a whole bunch of sentences with -n and post them to the forum to get help. People are pretty friendly and helpful here about providing corrections and explanations, as you may have noticed from other recent posts. Almost every single person here has been through the exact same experience you're going through now.

You could think of it this way. The default is no 'n'. When you see an 'n' added it conveys some specific extra meaning. It narrows down the interpretation.

So when you see a word terminating with 'n', you have to ask why is it there? After a while you will learn the various functions/meanings.

I have never seen any statistics on its use, but I thinks it's a safe bet that the most common use is to flag the object in a sentence, but what the next most common use would be I couldn't guess.

Don't forget to always wear your T-shirt emblazoned with 'Profesoro de la akuzativon' that will permit you to make any mistake with 'n' you wish.

EDIT: If you don't understand the joke, ask yourself what meaning does the 'n' in 'akuzativon' convey - answer, none.

When I started, I constantly made the mistake of using the -n where it didn't belong. It's different from our native language and takes time to get used to. Don't worry too much about it, Velleos. You'll make some mistakes at first but with practice, it quickly becomes second nature.

Also, just to give you some encouragement -- when speaking English, you consistently say "I saw him" instead of "I saw he", right? That's the object too! The rules in English for he/him, she/her aren't quite the same as Esperanto's rules for -n, but in time it will come equally as naturally, and "Mi vidas li" will strike your ear equally as wrong as "I see he".

It's very common for people whose first language is English to have difficulty with the accusative in Esperanto. Erinja's rules of thumb will help you lay a good foundation, so memorise them well. You may find it useful to read good Esperanto, and there is plenty of free material here. (I would complete the courses Ana Pana and Ana Renkontas, and then read Claude Piron's Gerda Malaperis!).