If I wanted a prophecy (for example) in a work of fiction to sound like it's old Esperanto, what would that involve?

I'm sure you'd use forms that are less common now, like ĥ in words that originally had it, 'uj' for country names, and use only words from the 'Unua Libro' and 'Fundamento' as your words stock, but what else would give something an old feel to something in Esperanto?

Well, one useful word that comes to mind is "ci" (thou). You could also pick through La Liro de la Esperantistoj, which has a few abandoned "reforms" from a period where the language was still unstable.

Have you looked into Arcaicam Esperantom, or would that go a little further than what you had in mind?

enwilson:Well, one useful word that comes to mind is "ci" (thou).

According to Bertilo Wennergren it's actually something of a misconception that ci was part of "old" Esperanto.

From La Detala lernu!-gramatiko...

9.5.2 Ci
Ci estas singulara alparola pronomo (kiu tute ne montras sekson). Ci kaj cia ekzistas nur teorie, kaj estas preskaŭ neniam praktike uzataj. Eblus imagi ci kiel pure singularan vi, aŭ kiel intiman familiaran (singularan) vi, aŭ eĉ kiel insultan (singularan) vi. Sed estas fakte tute neeble diri, kian nuancon ĝi montras, ĉar ĝi apenaŭ estas uzata. Iuj imagas, ke oni antaŭe uzis ci en Esperanto, kaj ke tiu uzo poste malaperis, sed fakte ci neniam vere estis praktike uzata. Ĝi nur aperis iafoje en eksperimenta lingvaĵo k.s. En normala Esperanto oni ĉiam uzadis nur vi kiel alparolan pronomon.

You also may appreciate a look upon the earlier stages of Zamenhof's works (Proto-Esperanto.)

Malamikete de las nacjes,
Kadó, kadó, jam temp' está;
La tot' homoze in familje
Konunigare so debá.

tommjames:

enwilson:Well, one useful word that comes to mind is "ci" (thou).

According to Bertilo Wennergren it's actually something of a misconception that ci was part of "old" Esperanto.

Maybe I got a bit confused on the implication of the "thou" in the English definition, which implies an antique formality in tone. If the nuance really is anybody's guess from lack of use, I withdraw that part of my suggestion, since nuance is basically what Oŝo-Jabe was asking about.

As I understand it, we are not talking about writing in ACTUAL old Esperanto, merely giving an "old-fashioned" tone to the words. Of course it should not be written in actual old Esperanto, since we want to make sure the reader understands it.

In this case:
- I agree with the suggestions to use the -uj- ending. You can also use endings in an archaic sense; e.g. "pomujo" = apple tree

- Studiously avoid "new" forms. So never write "devintus", always "estus devinta"

- This has nothing to do with Esperanto itself, but you can give a text an "old" feel by varying the word order. Putting the verb at the end (like Latin) tends to give this effect. That's what they did to Yoda in Star Wars, right? ("Strong in the force he was")

- Similarly, if you write in a somewhat "poetic" way (this also involves word order, as mentioned above, but I would include word choice in this. Independent roots that are seldom used can make the language sound more formal and archaic. So, you could use "trista" rather than "malfeliĉa", for example.

I recommend reading Zamenhof's translation of the Bible (Hebrew bible only, so stick to the Old Testament). You can find several versions of this online. I have frequently found that Zamenhof said something in a way that I wouldn't, whether it's because grammatical custom has changed somewhat, or whether it's because he's being poetic. In any case, religious texts are usually a great model for making a prophecy sound properly "prophetic", so the Esperanto Bible could definitely be a good model.

If you're serious about this, there's no substitute for actually reading a lot of the early texts to get a real feel for them. I don't believe there's a simple shortcut. Just applying a list of a few techniques or expression won't really create an authentic feel of early Esperanto beyond a few superficial trappings, any more than this forum thread would sound like old English just because we might all call each other "thee" or whatever. Fundamenta Krestomatio is a nifty place to start.