Can anyone help me differentiate the two? I'm kind of having a hard time understanding the explanation here.

Fou:Can anyone help me differentiate the two? I'm kind of having a hard time understanding the explanation here.

I've had some trouble with this too recently and I've been studying up on it this week. Hope these help:

La akvo bolas. - The water boils (or, 'the water is boiling'. It's an intransitive verb describing what's happening to the subject, i.e. the water.

Mi boligas la akvon. - I boil the water ('I am causing the water to boil', 'I am making the water boil.') The subject (I) am causing something to happen to the object (the water).

Mi sidas sur seĝo. - 'I sit on a chair', 'I am sitting on a chair.' There's no object. 'sidas' is describing what's happening to the subject.

Mi sidiĝas sur sego. 'I sit down on a chair.' This describes the action of sitting down in the chair, i.e. going from a standing position to a sitting position. There's no direct object with 'iĝ'. ('Seĝo' is an indirect object.)

I believe you can also get rid of the preposition and say it as 'Mi sidiĝis seĝon', yes?

I think the difference between 'boli' and 'boligi', and 'sidi' and 'sidiĝi' mixes up us English native speakers because we use the same word, 'boil', and 'sit', for both.

-ig = to make, to cause
-iĝ = to become, to change its state

Yes - the answer to your question really is that simple!

3rdblade:
I think the difference between 'boli' and 'boligi', and 'sidi' and 'sidiĝi' mixes up us English native speakers because we use the same word, 'boil', and 'sit', for both.

Yes, there are many English words, such as "burn", "boil", and "drown" that have both a transitive meaning and an intransitive meaning. "Sit" is a bit different. It has a transitive meaning too, as in "Sit the child on the sofa", but that's less common. In English, "Sit yourself down" is a bit folksy, but "sit" is used transitively with a reflexive pronoun. In French and German, that's the normal way of expressing it.

Anyway, in Esperanto, for better or worse, you must learn the actual dictionary meaning of the verb, which will specify whether it's transitive or intransitive. "Droni" is intransitive and it means to die by inhalation of water. To talk about drowning cats, or whatever, you must make it transitive, and Esperanto does this with the causative affix -IG-. So, dronigi means to cause to drown.

Even in English, you could say "I made the cats drown", but you normally wouldn't since it's simpler to say "I drowned the cats".

It's a bit misleading to think of the English word "drown" as the "equivalent" of the Esperanto word droni, because the English word has that extra transitive meaning, which is listed as an additional definition in dictionaries, which the Esperanto word doesn't have.

As you already noted, sidi means to be sitting. It describes a state, not an action. Or if you prefer, it describes a static action. Sidiĝi changes the meaning, but not the transitivity. It means to become seated, a non-static action (since it involves a change of state). Sidigi, on the other hand, is transitive, meaning to cause to be sitting.

I believe you can also get rid of the preposition and say it as 'Mi sidiĝis seĝon', yes?

Technically you could do this, but it wouldn't be adviseable.

I teach ig and iĝ with the "fill in the blank" method.

ig:
[adjective or noun root]+igi = to cause something to become [adjective or noun]
ruĝa = red; ruĝigi = to make something red
mola = soft; moligi = to make something soft [to soften something]
geedzoj = a husband and wife; geedzigi = to make someone a husband and wife [the officiant at a marriage i]geedzigas[/i] the couple who are getting married]

[verb root]+ igi = to cause someone or something to [verb root]
foriri = to go away; foririgi = to cause someone to go away, to make someone/something go away
manĝi = to eat; manĝigi = to make someone eat

ig words can take an object. The object is the thing that is being made to (turn red, get married, become soft, eat, go, etc)

I reddened [caused to become red] my cheeks with makeup => Mi ruĝigis miajn vangojn per ŝminko.
The priest married [caused to become husband and wife] the happy couple. = La pastro geedzigis la feliĉan paron.
John was unwelcome, so I made him go away = Johano estis malbonvena, do mi foririgis [for/ir/ig/is] lin.
Did you already feed the dog [cause the dog to eat]? = Ĉu vi jam manĝigis la hundon?

---

iĝ:
[adjective or noun root] + iĝi = to become [adjective or noun root]
ruĝiĝi = to become red
moliĝi = to become soft
geedziĝi = to get married [become married]

[verb root] + iĝi = to become [verb root]-ed
OR, occasionally, to initiate the action of [verb root] [this second meaning is where "sidiĝi" comes from, but this second meaning is no longer very widely used, except for a few change of state words like "sidi", "kuŝi" etc]
foririĝi = to initiate the 'going away' action [maybe I'd say "to up and leave" in colloquial English]
manĝiĝi = to become eaten [to get eaten, to be eaten]

I was embarrassed and my cheeks turned red = Mi embarasiĝis [became embarrassed] kaj miaj vangoj ruĝiĝis [became red].
The whole cake was eaten [became eaten] = La tuta kuko manĝiĝis.
[as you can imagine, the -iĝ- ending is sometimes used for things that end up with a passive voice in English; also in Esperanto, the alternate wording for that last sentence could have used a passive voice form, that is, "La tuta kuko estis manĝita"]

iĝ words don't take an object, as someone has already mentioned. The idea of becoming is closely tied up in iĝ, and "becoming" is an action performed on the subject, not on some external object.

erinja:
Did you already feed the dog [cause the dog to eat]? = Ĉu vi jam manĝigis la hundon?

Then would the case of:
Ĉu vi jam manĝiĝis la hundon?

contrastingly mean "Did you already make the dog become eaten?", or something else?

Just trying to nail down my less than stellar understanding of the differences too, though your explanation helped me a great deal.

erinja:
foririĝi = to initiate the 'going away' action [maybe I'd say "to up and leave" in colloquial English]

Can't say I've come across this one before. Sounds like a complicated way of saying 'foriri'. I'm having a hard time trying to work out why it should help by adding 'iĝi'?! In fact, does it even make any sense?

I had a quick look for this in Kukolo and found a mere 4 examples, all of which seem to come from the same text.

erinja:...also in Esperanto, the alternate wording for that last sentence could have used a passive voice form, that is, "La tuta kuko estis manĝita"]

Yes, I think this is the preferable form.

Regarding igi, given that that means "to make become", how do you express "to make continue to be" ? An example is this line from the song The Red Flag (which I daresay many an Esperantist has sung):

"We'll keep the red flag flying here"

NB, there's a translation by "GramTrans" out there that I think's wrong.

Chainy:Sounds like a complicated way of saying 'foriri'. I'm having a hard time trying to work out why it should help by adding 'iĝi'?!

In an intransitive verb -iĝ adds the idea of commencement, so "start leaving" rather than just "leave". Though I'd much prefer ekforiri myself. Use of -iĝ seems to me to make much more sense on intransitives that imply state, like sidi, boli etc.

Just a small point to add. When using -ig on a transitive verb the result can have either an active or a passive sense, so manĝigi can just as well mean "to make eaten" as "to make eat". You can say both "manĝigi infanon" or "manĝigi supon al infano" and they're both valid, even though in one case the object is that which eats, and in the other it's that which is eaten. Some other examples of verbs that often have the passive sense are vidigi (make seen, show) and sendigi (have sent). You might say Baldaŭ mi sendigos vian diplomon. Kiam vi ricevos ĝin, vidigu ĝin al via familio.

It's probably true to say however, that ig-transitives usually have the active meaning.