Two forms of 'to be' - predicative vs. existential?

[fusijui]

Yeah, I think the term "existential copula" was enough to make me think the question was about Tibetan-style yin/yod distinctinos, rather than the Spanish sort of thing. Never mind!

[Rounin Ryuuji]

Also like Japanese da (formal: desu) vs aru (formal: arimasu) or iru (formal: imasu). Da and desu are used with adjectives or equating nouns (I am a teacher. = Watashi wa sensei desu.). Whereas aru and arimasu, and iru and imasu, are used for something - or someone - existing in a place, though these can also extend to having something (I have money (Lit: For me, money exists) = Watashi wa okane ga arimasu.)

The split between aru and iru is based on animacy, which you wouldn't need to include in your conlang.

Some notes on the etymology of these forms:

いる (iru), Historical Kana ゐる (wiru), Old Japanese wiri, historically meant "sit".

As far as I can tell, ある (aru) is a regularised form of the Classical copula あり (ari), which doesn't appear to have a discernible etymology beyond this, though it is superficially similar to 歩く (aruku, "walk"), 歩む (ayomu, "walk, step") 歩ぶ (ayobu), this odd /r/~/j/ alternation appearing in some other situations in Old Japanese (imperative endings in -ro/-yo, and some passive forms). I think there might be a distant connection here, albeit a very distant one. I'm also not sure when it shifted between being the copula and being an existential verb for inanimate objects.

The modern copula だ、です (da, desu), dialectally also じゃあ (jā) or じゃ (ja), appears to be a contraction of である、であります (de aru, de arimasu), note also the negative is usually じゃない (ja nai) or じゃないです (ja nai desu) forms ではない (de wa nai, literary), ではありません (de wa arimasen, more formal than ja nai desu), and じゃありません (ja arimasen) are also attested. The particle で (de), ordinarily locative, is a contraction of にて (nite). I've encountered the idea that the particles の (no, a genitive particle), な (na, a connecting particle appearing in some archaic words, not the same as the modern adjectival marker) にて/で (nite/de), and に (ni, a directional or locative) were once conjugations of an archaic copula, which might've been preserved with the Old Japanese perfective ending ぬ. It's possible that the Old Japanese genitive particle つ (tsu), the verb connector て (te) and an alternate Old Japanese perfective ending (also つ), might have been connected to a different by then obsolete copula, but this is only my personal speculation.

A form historically をる (woru), now usually おる (oru), a variant of いる (which was historically ゐる wiru), also exists. The form をる/おる is of disputed etymology. Some sources give it as a contraction of *wi aru, but this would be expected to yield a form *eru, *ieru, or *yaru — (note that eru , ieru, and yaru do exist, but are unrelated words meaning "be able", "be able to say" or "recover, heal", and "do", respectively). It's probably worth noting, by contrast, that なる (naru) "become" probably descends from にある (ni aru, which would yield an expected *neru (while a word of this form exists, it is unrelated, and means "sleep"), so the entire eclipsing of /i/ when followed by aru is precedented.

Possibly useful fodder for what to do with obsolete copulas as opposed to where to get new ones.

[hwhatting]

For what it's worth, ser and estar derive from the latin for "sit" and "stand" respectively.

True for the second, but ser mostly*) continues the Latin forms of esse "to be" (the infinitive goes via a Romance *essere).
*) Give and take some analogical formations and newly created forms like sido - Latin simply didn't have a past participle of esse.
FWIW, Irish is and tá also go back to PIE *h1es- "be" and *steh2- "stand", respectively.

[Darren]

For what it's worth, ser and estar derive from the latin for "sit" and "stand" respectively.

True for the second, but ser mostly*) continues the Latin forms of esse "to be" (the infinitive goes via a Romance *essere).
*) Give and take some analogical formations and newly created forms like sido - Latin simply didn't have a past participle of esse.

A good portion of ser does come from sedēre - the infinitive actually comes from sedēre, hence why it was seer in Old Spanish. So do the present subjunctive and the imperative. Still, the majority of the conjugation, especially the most common forms, is from esse.

[hwhatting]

A good portion of ser does come from sedēre - the infinitive actually comes from sedēre, hence why it was seer in Old Spanish. So do the present subjunctive and the imperative. Still, the majority of the conjugation, especially the most common forms, is from esse.

OK, thanks for the correction!