Hi all.

First time poster.

Please forgive the obvious ignorance here, but my wife and I are confused regarding when to use -n.

Please note, our 1980s Queensland education system dropped the ball on grammar for functional linguistics, so simple explanations would be great. Furthermore, as brilliant at they are, Lernu, Duolingo etc. don't or can't explain in terms we can comprehend.

We're beginners, so please be kind. A virtual hug and high-five for the first person to explain!

There is an English summary on the Duolingo forum When to use the -n ending. I also recommend reading the comments by Salivanto and yours truly (I go there by name Juha_Metsakallas).

Bonvenon al Esperantujo!

I could use a virtual hug.

The -n ending for a noun (e.g., libron instead of libro) is used when the object the noun signifies is the recipient of the action of the verb. Example: Mi legas la libron. I read the book. The book is the "direct object" of the action of reading.
Mi trinkas akvon: I drink water. The akvo is the direct object of trinkas and so is written as "akvon."

Some verbs (notably esti (to be), but also ŝajni (to seem) and a few others) do not carry the idea of action but simply are asserting some sort of an identity (or lack of it, in the case of ne esti, for example, or ne ŝajni) between the subject noun and the predicate noun. Thus the noun in the predicate is not the recipient of any action, and so it does not get the -n ending.

Tio estas libro. That is a book. No action, no -n.
But: Tio estas libro, kion mi legas. That is a book, which I am reading (or: That is a book that I am reading): "Libro" lacks the -n because it is not the objection of any action—the phrase says simply that "tio" and "libro" are the same, but kio gets the -n because in the phrase "kion mi legas" kio is the direct object of legas: kio is being read, so it must be kion in the sentence

Useful terminology: the -o ending is the "nominative" case — there we are just naming the object — and the -on ending is the "accusative" case. This quote may be helpful:

The accusative case (abbreviated acc) of a noun is the grammatical case used to mark the direct object of a transitive verb. … The syntactic functions of the accusative consist of designating the immediate object of an action, the intended result, the goal of a motion, and the extent of an action.

That's from a fellow Australian. UPDATE: Although on the whole it's a good column, it does include one obvious error. He writes:

I gave the cat some food.
I (subject) gave (verb) the cat (direct object) some food (indirect object).

"cat" is the indirect object and "food" is the direct object. You're giving food to the cat. One obvious way to see this is that indirect objects can be made objects of a preposition: "I gave to the cat some food." The sentence is similar to "I mailed my friend the letter." Here it should be obvious that what is mailed is the letter and not my friend. "Letter" is the direct object, "friend" is the indirect object. (That sentence could similarly be rewritten with a preposition: "I mailed to my friend a letter.")

Check also the grammar in Lernu: click the "hamburger" menu indicator at the right of the green band above, and choose "Grammar," then look over 12.1 and 12.2.

-n has a few other uses. Normally Esperanto nouns in a prepositional phrase use the nominative case (en la domo = in the house), but the accusative is sometimes used to show direction (en la domon = into the house — that is, moving from outside the house to inside the house). Those uses will be described later in the course. The main use at the beginning is to show the noun is the direct object of a transitive verb in the active voice: "transitive" = conveying action, "active voice" meaning it's active.

Verbs can be transitive (conveying action: "hit" is the usual example) or intransitive (no action: "is" or "seems" are examples, but also verbs like "smell" ("the steak smells good": no action, just asserting a descriptive attribute of the steak) and "taste" ("the cake tastes good": again no action, so the verb is intransitive)).

I'm happy to answer any questions. What's odd is that the more you work at it, the more it becomes clear to the point that eventually don't even think about it. In Artificial Intelligence a software structure call a "neural net" is often used, and you train a neural net by giving it a lot of instances — i.e., you exercise it. For example, if you want your AI to recognize cat images, you show it hundreds of thousands of images, marked as cat images and images that are not cats. The AI program gradually "learns" the difference and eventually can immediately tell whether an image is a cat or not.

In learning a language the repetition of practice is just like training an AI neural net, because what one is doing is training the original neural net, the brain. Repeating the exercises over and over gradually rewires the brain so that you just automatically "know" what to do without thinking about it.

I mention this because when I realized I was training a neural net, I found much more patience and less frustration with my practice. FWIW, I wrote up what I've discovered about using Lernu's course. I'm using it alongside Duolingo, and Duolingo's exercises are much more obviously neural-net training.

Hope this helps.

Tio estas libro, kiun mi legas.
This is another thing, which difficult for English speaker - to use 'kio' or 'kiu'

action -> transitive
no action -> intransitive

This doesn't work at all.
"Mi kuras" and "mi dancas" is all about actions, moving limbs, breathing heavily, shoving others out of the way, and yet both verbs are intransitive (unergative to be precise).

However "li ŝatas min" and "li amas min" involve no action at all, they describe a state (of mind, emotion, etc), and yet both verbs are transitive.

Interesting point. I think "action" in this case is to some degree a term of art that refers to the object of the verb's direction or thrust. Perhaps "action" is a bad word, and I'd be interested in a better word.

In "mi kuras" there is action (of a physical sort) but the verb is not delivering any .... what do you want to call it? ... to an object. In mi amas vin there is not physical action, but the object (vin) is the recipient of the love.

I have found in practice that thinking of the verbs as directing some sort of energy (not always physical energy) has been helpful: mi havas libron describes no physical activity, but the book is the recipient of something from the verb — of being had, in effect.

What do you propose?

Perhaps just drop "action" and say the direct object is the recipient of whatever the verb is doing. In "I love you," "you" is the recipient of the love. In "I like tomatoes," "tomatoes" are the recipient of the liking.

In contrrast, in the case of "I run" or "I dance," nothing receives the running or the dancing.

Perhaps "target" would be an acceptable word: transitive verbs in the active voice have a target? Does that work for you?

Some actions need two objects, one is direct, the other is indirect:
Give me a pen! - Donu al mi plumon!
English, in this case, does not mark indiect object. But you can change order:
Give a pen to me! - Donu plumon al mi!

Leisureguy already said about it - I didn't noticed it in the long message before.

nornen:

action -> transitive
no action -> intransitive

This doesn't work at all.
"Mi kuras" and "mi dancas" is all about actions, moving limbs, breathing heavily, shoving others out of the way, and yet both verbs are intransitive (unergative to be precise).

However "li ŝatas min" and "li amas min" involve no action at all, they describe a state (of mind, emotion, etc), and yet both verbs are transitive.

I got to thinking more about this. It seems to me that a verb describes a fareco (I'm gong to mix Esperanto and Engoish a bit in search of the right concept.) Here I restrict myself to verbs in the active voice.

Case 1: The verb's fareco is complete in itself and the predicate consists only of the verb. (to run and to cook, in the examples you offer). Or "Is Tom here?" ans: "he is." "Your fate awaits."

Case 2: The fareco of the verb links a characteristic to the subject. For example, "la kuko estas bruna," or "la knabo ŝajnas bona" or "the cake smells good." In English, to be, to seem, to taste, to smell, to look (meaning to appear) are used in that way. "That looks good" uses the verb to link a characteristic ("good") to the subject ("that").

One point: it's important to know whether the characteristic following the verb describes the subject (and thus is an adjective) or describes the verb (and thus is an adverb). In English we have good (bona) as an adjective and well (bone) as an adverb.

The dog smells good (i.e., not stinky)
The dog smells well (i.e. its smelling ability is good)
The dog smells bad but well (it stinks but has good smelling ability).

However, in Esperanto one writes: "La kuko gustas bone" for "The cake tastes good." The descriptive word is intended to describe the noun (kuko/cake) and not the verb. The Esperanto version uses an adverb (as in "The cake tastes well") with the predicate (bone) describing the verb and not the cake (which would call for an adjective).

So I'm puzzled on this point.

Case 3: the verb conveys some fareco from subject to an object: I love you" (where "you" receives the fareco of love from "I"). Same with "mi batas la pilkon": the pilko is the recipient of the fareco from mi. In English "smell" can be used in this sense, too: I smell the dog. That is, in English "smell" can be transitive or intransitive, depending on usage.

Esperanto verbs usually are one or the other and -iĝ- is used to make a transitive verb intransitive and -ig- is used to make an intransitive verb transitive. "Boli" (to boil) is intransitive in Esperanto (as in "the water boils" and to make it transitive (as in "I boil the water"), you use boligi (to cause to boil). "Bati" (to hit) is transitive (mi batas la pilkon), and "batiĝi" is intransitive (la pilko batiĝas — the ball is hit).

Google translate:
dog smells well but stinky => hundo odoras bone sed ruza

I'm still puzzled by the -e ending of bon- in "La kuko gustas bone.' We don't write "La kuko estas bone," but rather "La kuko estas bona" — an adjective, because we're describing the cake (a noun) rather than the verb I suppose in "la kuko gustas bone" the idea is that we are describing the verb and thus the adverbial form of bon-. We specifying more precisely what "gustas" signifies in this case.