sudanglo:
Mi konsentus ke la uzo de la akuzativo estus ebla rimedo por distingi inter Ĉu vi konas mian amikon, Paŭlo? (mi parolas al Paŭlo) kaj Ĉu vi konas mian amikon Paŭlo? (Paŭlo estas la amiko pri kiu mi parolas), sed tamen mi preferus la nominativan uzon.

Pravas. En skribo oni povas uzi komon por distingi, sed en parolo oni uzas aŭ paŭzon (parolas al Paŭlo) aŭ akuzativon (pri Paŭlo). Aŭ plej verŝajne oni ne uzas nomon, kiam oni parolas al sia amiko Paŭlo.

Certe, vokativo estas bone distingebla - per komo en skribo, per intonacio en parolo.
Mi parolas pri distingo de predikativo.

Eble uzado de akuzativo oni distingas
amikon Paŭlon, amikinon Annan - homo, li/ŝi
lingvon Esperanto - objekto, ĝi
- same kiel en pasivo (far de/per)

Metsis:

sudanglo:
Mi konsentus ke la uzo de la akuzativo estus ebla rimedo por distingi inter Ĉu vi konas mian amikon, Paŭlo? (mi parolas al Paŭlo) kaj Ĉu vi konas mian amikon Paŭlo? (Paŭlo estas la amiko pri kiu mi parolas), sed tamen mi preferus la nominativan uzon.

Pravas. En skribo oni povas uzi komon por distingi, sed en parolo oni uzas aŭ paŭzon (parolas al Paŭlo) aŭ akuzativon (pri Paŭlo). Aŭ plej verŝajne oni ne uzas nomon, kiam oni parolas al sia amiko Paŭlo.

Ekde kiam la vorto "pri" indikas la akuzativon?

Mi pensas, ke oni devus diri Ĉu vi konas mian amikon, Paŭlo? se oni parolas al Paŭlo, kaj oni devus diri Ĉu vi konas mian amikon, Paŭlon? se oni demandas pri Paŭlo, sed ne parolas al li.

Metsis:

MiMalamasLaAnglan:
Kial oni ne dirus, ke la nomo de tiu lando estas aŭ Ĉinio aŭ Ĉina Respubliko?

There is a gratis booklet titled Konciza klarigo pri la landonomoj en Esperanto by Anna Löwenstein, that brings some light to the land names, which are otherwise a mess.

The old suffix -ujo was based on the stupid idea, that countries are ethnically homogenous. Nowdays most of the country names are expressed with a suffix -io, e.g. Ĉinio. This country name -i is not applied to adjectives referring to the country, thus ĉina. When it comes to China, we the laowais (foreigner in Mandarin) tend to fail to realise, that there is no such ethnic group as Chinese. See Oficiale konfirmitaj etnaj grupoj en la ĉeftera Ĉinio for the official ethnic groups in Ĉina Popola Respubliko and Demographics of Taiwan for ethnic groups in Respubliko Ĉinio.

I personally would like to a more clear distinction between citizenship and ethnicity. This can be (relatively) easily achieved with the suffix -ano. For instace Ĉi tiu hano estas (popolrespublika) ĉiniano (citizen of PRC), sed tiu hano estas (respublika) ĉiniano (citizen of ROC). Mi renkontis du rusojn. La unua estis germaniano kaj la dua rusiano.

I meant "Ĉina Respubliko" as opposed to "Ĉinio-Respubliko". I guess you could also say "Ĉinia Respubliko".

MiMalamasLaAnglan:
I meant "Ĉina Respubliko" as opposed to "Ĉinio-Respubliko". I guess you could also say "Ĉinia Respubliko".

While you could, Ĉina Popola Respubliko (中华人民共和国) and Respubliko Ĉinio (中華民國) are the official names of those two countries. There are also two Kongos, Respubliko Kongo (Repubilika ya Kôngo) and Demokratia Respubliko Kongo (Repubilika ya Kôngo ya Dimokalasi).

A political opinion:
I'm reluctant to give any political entity exclusive right to a term, which has been used about something else. Note, that this reluctance has nothing to do, what I think about different political systems. Thus

• China ≠ People's Republic of China, but a more vague area of Imperial China, the area varied during the centuries; if you talk about currently existing states, you have to be more specific
  
• Europe ≠ EU, because Europe stretches from Atlantic to Ural, from Arctic Sea to Mediterranean
  
• America ≠ USA, because America stretches from Pacific to Atlantic, from Arctic Sea to Southern Ocean

Or earlier Germany ≠ Federal Republic of Germany in contrast to German Democratic Republic. And I never mixed Russia with Soviet Union.

Metsis:
While you could, Ĉina Popola Respubliko (中华人民共和国) and Respubliko Ĉinio (中華民國) are the official names of those two countries. There are also two Kongos, Respubliko Kongo (Repubilika ya Kôngo) and Demokratia Respubliko Kongo (Repubilika ya Kôngo ya Dimokalasi).

A political opinion:
I'm reluctant to give any political entity exclusive right to a term, which has been used about something else. Note, that this reluctance has nothing to do, what I think about different political systems. Thus

• China ≠ People's Republic of China, but a more vague area of Imperial China, the area varied during the centuries; if you talk about currently existing states, you have to be more specific
  
• Europe ≠ EU, because Europe stretches from Atlantic to Ural, from Arctic Sea to Mediterranean
  
• America ≠ USA, because America stretches from Pacific to Atlantic, from Arctic Sea to Southern Ocean

Or earlier Germany ≠ Federal Republic of Germany in contrast to German Democratic Republic. And I never mixed Russia with Soviet Union.

But shouldn't you say Respubliko Ĉinia, Respubliko Konga, or Demokratia Respubliko Konga? There should be only one noun, right?

MiMalamasLaAnglan:
But shouldn't you say Respubliko Ĉinia, Respubliko Konga, or Demokratia Respubliko Konga? There should be only one noun, right?

Hmm, that's actually a good question. In English, in my native Finnish and possibly in several other languages a genitive expression is used

• Republic of China, Kiinan tasavalta
  
• Republic of Kongo, Kongon tasavalta

For the Respubliko Ĉinio form I reason this way [read: I 'm probably wrong].

Naturally the genitive above doesn't denote any possession, but acts as glue between two nouns. However the E-o preposition de, despite being woefully overloaded with several meanings, cannot for once be used for such marking. IMHO, the rule 12 would be too stretched here.

Since a compound word (Ĉinirespubliko) is out of the question here, the remaining alternatives are

• Respubliko Ĉinio
  
• Ĉinia Respubliko

The first alternative is based on the rule, that has been discussed in this thread, i.e. the first noun, Respubliko, defines what the second noun, Ĉinio, is. In other words it answers the question, what China is. It's not a sea nor an island, but a republic.

The second alternative is based on the common E-o usage of adjective as glue between the two nous. I admit, that this romance language pattern is a little strange to me being used to compound words and genitive. I understand it so, that the adjective ĉina (without i) would mean there is some Chinese trait or feature how a republic could be run. The adjective ĉinia (with i) just shifts this trait or feature be China-land-ian or -ish, which doesn't make sense. Compare this with Demokratia Respubliko Kongo, where demokratia describes the republic and not Kongo.

Thus of the alternatives Respubliko Ĉinio is the best to describe, what Ĉinio is. It's a republic. Also not a minor argument in favour of this form is, that the countries themselves use such official names.

Metsis:
Hmm, that's actually a good question. In English, in my native Finnish and possibly in several other languages a genitive expression is used

• Republic of China, Kiinan tasavalta
  
• Republic of Kongo, Kongon tasavalta

For the Respubliko Ĉinio form I reason this way [read: I 'm probably wrong].

Naturally the genitive above doesn't denote any possession, but acts as glue between two nouns. However the E-o preposition de, despite being woefully overloaded with several meanings, cannot for once be used for such marking. IMHO, the rule 12 would be too stretched here.

Since a compound word (Ĉinirespubliko) is out of the question here, the remaining alternatives are

• Respubliko Ĉinio
  
• Ĉinia Respubliko

The first alternative is based on the rule, that has been discussed in this thread, i.e. the first noun, Respubliko, defines what the second noun, Ĉinio, is. In other words it answers the question, what China is. It's not a sea nor an island, but a republic.

The second alternative is based on the common E-o usage of adjective as glue between the two nous. I admit, that this romance language pattern is a little strange to me being used to compound words and genitive. I understand it so, that the adjective ĉina (without i) would mean there is some Chinese trait or feature how a republic could be run. The adjective ĉinia (with i) just shifts this trait or feature be China-land-ian or -ish, which doesn't make sense. Compare this with Demokratia Respubliko Kongo, where demokratia describes the republic and not Kongo.

Thus of the alternatives Respubliko Ĉinio is the best to describe, what Ĉinio is. It's a republic. Also not a minor argument in favour of this form is, that the countries themselves use such official names.

Why isn't Respubliko de Ĉinio correct?

If it is the Republic of China, then can't it also be described as the Chinese Republic?

I know that this isn't necessarily a reliable source, but https://eo.wikipedia.org/wiki/%C4%88inio_(%C5%9Dta... says that it is called Ĉina Popola Respubliko.

I can see at least two arguments here.

Firstly what a country is called, is one of the rights of sovereign countries. If a country wants to be called "Kingdom of Naysayers", they are fully entitled to so. A rule of diplomacy is, that other countries follow the naming as closely as possible, so that country would ,for instance, be called Königreich der Neinsager by Germany. So if Respubliko Ĉinio is an adequate translation of 中華民國, so be it.

Secondly the E-o prepositions should be understood quite literally. I Finnish the genitive case is used very liberally as a glue between nouns, even the English usage of the preposition "of" is more liberal than of the E-o preposition de. Plena Ilustrita Vortaro lists the 13 cases (not 12 as I erroneously wrote earlier), where you can use de. As far as I can decipher none of them would cover Respubliko de Ĉinio. Even the 12th case IMHO requires, that the former noun is a more or less natural feature of the latter one, la prezo de pano. So a state, China is this case, would have a feature called republic. Can a certain political system be a natural feature of a state? IMHO, no.

Metsis:Königreich der Neinsäger

Aldoneteto: "Neinsager" kaj ne "Neinsäger".
sagen (diri) -> Sager (diranto)
sägen (segi) -> Säger (seganto)

Neinsäger = Naysawyer