Translations of "to be".

[Ser]

Don't get wrong, in a sentence like Aquí [exists] un perro we must use hay because we're speaking of a dog not the dog, as I said before. The use of haber here is impersonal. So we'll say Aquí hay un perro (perro is complement, not subject). If we know the dog we'll say Aquí está el perro. Note the difference, please.

I just realized something, maybe it's just a simple dialectal difference?

I found this interestingly similar discussion at the WR forum, where a speaker from Mexico insists that estar + the indefinite article is alright, but the ones from Spain insist that it isn't. (LOL) I still insist that following it with either article is fine (at least IMD), and that there's a small difference in meaning/usage between them.

As an aside, this related discussion too, where the opposite is argued (haber + the definite article). This one does feel ungrammatical to me though.

What Mexican? The one who says that Allí hay un libro de inglés is «wrong»? What credibility I should expect from that guy after reading this?

The credibility of being a native, regardless of his judgement of haber + un? Also, regarding googling "aquí está un" and finding sites with English grammar, were you just referring to that stupid machine-translated blog sonfamosos.com with a ridiculous Google rank? Did you check all other results below? What do the others natives think?

[Izambri]

Don't get wrong, in a sentence like Aquí [exists] un perro we must use hay because we're speaking of a dog not the dog, as I said before. The use of haber here is impersonal. So we'll say Aquí hay un perro (perro is complement, not subject). If we know the dog we'll say Aquí está el perro. Note the difference, please.

I just realized something, maybe it's just a simple dialectal difference?

I found this interestingly similar discussion at the WR forum, where a speaker from Mexico insists that estar + the indefinite article is alright, but the ones from Spain insist that it isn't. (LOL) I still insist that following it with either article is fine (at least IMD), and that there's a small difference in meaning/usage between them.

As an aside, this related discussion too, where the opposite is argued (haber + the definite article). This one does feel ungrammatical to me though.

What Mexican? The one who says that Allí hay un libro de inglés is «wrong»? What credibility I should expect from that guy after reading this?

The credibility of being a native, regardless of his judgement of haber + un? Also, regarding googling "aquí está un" and finding sites with English grammar, were you just referring to that stupid machine-translated blog sonfamosos.com with a ridiculous Google rank? Did you check all other results below? What do the others natives think?

Bearing in mind that I speak Spanish as an almost-native (I live in Barcelona and learned Castilian from the 1st year of school), and bearing in mind too that Allí hay un libro de inglés is perfectly correct Spanish and the first construction of that kind of sentence one should have in mind when speaking Spanish.. I say yes, I don't give any credibility to this guy, who says Allí está un libro de inglés as the only correct form of the sentence. And as I said some posts ago, Google is not the best tool to confirm or deny such things.

I repeat word by word what I said in my definitive message, the one that concludes all this:

«Usage doesn't mean it's correct. Doing a quick search through Google myself I see that those who write aquí está un [noun] have other incorrections; many are copies of English syntax.

Don't get wrong, in a sentence like Aquí [exists] un perro we must use hay because we're speaking of a dog not the dog, as I said before. The use of haber here is impersonal. So we'll say Aquí hay un perro (perro is complement, not subject). If we know the dog we'll say Aquí está el perro. Note the difference, please.»

[zompist]

My wife, a native speaker, confirms Izo's basic point.

However, when I asked specifically about "Aquí está un perro", she came up with a context that would allow it, at least in her hometown (Iquitos, Peru)— something like this:

A: No hay lagartos en este pueblo. ("There are no lizards in this town.")
B (pointing): Mm? Aquí está un lagarto. ("Mm? There's a lizard (right there).")

She suggests that it has an air of contradiction, compared to "Aquí hay un lagarto" which simply introduces the lizard.

[Izambri]

My wife, a native speaker, confirms Izo's basic point.

However, when I asked specifically about "Aquí está un perro", she came up with a context that would allow it, at least in her hometown (Iquitos, Peru)— something like this:

A: No hay lagartos en este pueblo. ("There are no lizards in this town.")
B (pointing): Mm? Aquí está un lagarto. ("Mm? There's a lizard (right there).")

She suggests that it has an air of contradiction, compared to "Aquí hay un lagarto" which simply introduces the lizard.

Interesting. That woldn't happen in Spain, AFAIK, and it stills sounds odd to me. In Spain we would hear:

A: No hay lagartos en este pueblo.
B: (pointing) Hm? Aquí hay uno/un lagarto.

Another use of estar + un came to my mind after posting my last message: Está un tío en el suelo y va y se cae "There's a dude on the floor and he falls", although Hay un tío en el suelo y va y se cae is also correct and common.

[Ser]

To settle this for good, I think I'm just gonna go ahead and revive the use of pronominal ser.

Érase un perro aquí. (¿"Esse un perro aquí" en el presente?)

[Izambri]

To settle this for good, I think I'm just gonna go ahead and revive the use of pronominal ser.

Érase un perro aquí. (¿"Esse un perro aquí" en el presente?)

Would be He aquí un perro, which is the same as Hay aquí un perro or Aquí hay un perro. The verb is haber.

[Ser]

Hey, that's a funny grammaticalization of what otherwise was "I have here" too.

It's interesting that this use of pronominal ser is pretty much limited to introducing tales, apparently.

[Khvaragh]

Written Arabic:

1) الكلب حيوان.‏ /al-kalb-u ħajawaːn-un/
DEF-dog-NOM.DEF animal-NOM.INDEF

Seems fine. You can also say:
/al-kalbu huwa ħajawa:-un/
"The dog, it is an animal"
Which tells us unquestionably, the dog is an animal.

2) الكلب في الحديقة.‏ /al-kalb-u fiː l-ħadiːqat-i/
DEF-dog-NOM.DEF in DEF-garden-OBL.DEF

I would say: /in:a l-kalb-a fi: l-ħadi:qat-i/
"[Indeed] the dog [is] in the garden."
/in:a/ tells us that it is a fact that the dog is in the garden, where as the former, gives the gives the impression of here-say, though it is acceptable.

3) في الحديقة كلب‏.‏ /fiː l-ħadiːqat-i kalb-un/
in DEF-garden-OBL.DEF dog-NOM.INDEF

No. There is a perfectly good existential in Arabic: /wudʒida/ (lit. "is found") (ka:na is for statements and is closer to a copula; the mental distinction I give them is that ka:na is semantically stative, whereas wudʒida seems more dynamic). The above is a very colloquial usage.
/wudʒida fi: l-ħadi:qat-i kalbun/ or /judʒidu fi: l-ħadi:qat-i kalb-un/
"There is a dog in the garden"

You can also use the passive participle instead:
/ka:na mawdʒu:d-an fi: l-ħadiqa:t-i kalb-un/ or /jaku:nu mawdʒu:d-an fi: l-ħadi:qat-i kalb-un/
"There is a dog in the garden"
(literally, there was/is found a dog in the garden)

4) ها هو كلب.‏ /haː huwa kalb-un/
hā 3SG.M dog-NOM.INDEF
(hā = presentative particle)
هنا كلب /hunaː kalb-un/
here dog-NOM.INDEF

The first is much better, but somewhat archaic. /huna:/ is not a presentative, it means "in this place is a dog." You could also say:
/ha:ða: huwa kalb-un/
"this is a dog."
Keep in mind that ha:ða: is actually a compound of the archaic presentative /ha:/ and the original relative/demonstrative ðu:/ða:/ði:, which has become nominalized. As such, ha:ða:/ha:ða:hi replace them in many places; al:aði: and al:ati: also are compounds from ðu:.

Talking about Arabic in particular, there's a small series of adjectival verbs that mean "to be or become X". I'm not sure about the actual nuances between these and just using the copula (or zero copula) + an adjective though. These are typically form I with the transfix CaCuCa, and form IX (ʾi)CCaC:a, e.g. بعد /baʕuda/ "to be/become far", احمر /(ʔi)ħmarːa/ "to be/become red, to blush".

بعد الكلب ولكن استطعت أن أراه.‏ /baʕuda l-kalbu wa-laːkin i statˤaʕtu ʔan ʔaraː-hu/
be.far.3SG.PRF DEF-dog-NOM.DEF and-but be.able.to.1SG.PRF ʾan see.1SG.SUBJ-him
'The dog was getting far but I was able to see it.'
(i = epenthetic sound, ʾan = particle introducing a conjugated verb in a periphrasis)

There is no copula in "becoming verbs" (ka:na wa ixwa:tuha:); there is no need for them, because the sense of the copula is embedded in the verb already. If you use the so-called copulas of Arabic, there are different results.
For ka:na :

/kuntu abʕudu min:aka/
"I used to be far from you"

For pronouns:
/baʕuda huwa l-kalb/
"He was far away, [that] dog"

4 uses the presentative particle ها hā, and you *could* analyze the 3SG pronoun here to be the copula. I think the presentative situation is something exclusive to the present, isn't it? The second structure is a simple "here [zero copula] dog".

It is the copula. Or at least it's described as such (I would more closely analyze there as being a zero copula there which /huwa/ stands in for). This is perfectly good Arabic, and very common, not just is this structure, but also to give emphasis, etc.

/ʔuħibbuka anta/
"I love you."

***
I should try out Syriac next, if I have time; the distinctions are much more subtle than in Arabic.