English: relative clauses describing pronouns

[Vardelm]

Can a relative clause ever modify the pronoun "it" in English?

It that quacks like a duck...
It which quacks like a duck...

Other pronouns aren't an issue. It just struck me that "it" is different. I look at those examples and think "that SHOULD be OK, but it just ain't!"

[Rounin Ryuuji]

I think I would describe it as having a suppletive form that when following which — that which, but not *it which — while the phrase *it that is normatively replaced by what — That which quacks like a duck..., What quacks like a duck...; other possible suppletive forms might include The thing that (quacks like a duck), Anything that (quacks like a duck) and so on and so on.

I'd never noticed it lacked this property before now.

[Moose-tache]

When a pronoun has a relative clause I always stress it more overtly: "I love us, who have nothing to lose." In this environment, "it" changes to "the one." A similar divide exists for apposatives: "He, the duke of Gloucester," but not "It, the dog in my dream."

The West Germanic languages in general have a history of trading third person pronouns and demonstratives back and forth across part-of-speech classes, so I wouldn't be surprised if this behavior predates English as a separate language. Does anything screwey like this happen in German, say, in the usage of pronominal der vs. er?

[zompist]

To me any of the personal pronouns followed by a relative clause sound archaic.

"I who speak to you am he"
"He who has the mark on his brow, let him face the east and recite"

I mean, it sounds like a fantasy novel. If I try to update it, it's even weirder:

"I who tweet this message am he"
"He who initiated the Zoom call can mute the others."

Not ungrammatical, just old-fashioned.

[Vardelm]

To me any of the personal pronouns followed by a relative clause sound archaic.

Yeah, I agree. I wondered if maybe "it which" or "it that" might have been grammatical at one point, but has completely phased out.

"He who initiated the Zoom call can mute the others."

This sounds archaic, as mentioned.

"He that initiated the Zoom call can mute the others."

This sounds a bit less archaic.

"Whoever initiated the Zoom call can mute the others."

This is what I would generally expect to hear now.

[Moose-tache]

To me any of the personal pronouns followed by a relative clause sound archaic.
"I who speak to you am he"

This is exactly why I used examples where the pronoun carrying the relative clause was an object, not a subject. "He who..." is a special phrase, often used in topicalization, and it does sound archaic. But compare:
"I, who always wash the dishes, ask that you use a clean fork."
vs.
"Don't ask how the dishes got clean. You saw me, who always does the dishes, standing right there!"
The second, to me, is free of any archaicness that may pertain to the first.

[zompist]

"Don't ask how the dishes got clean. You saw me, who always does the dishes, standing right there!"

That doesn't strike me as wrong, but it's not colloquial either. I'd say "me, the one who always does the dishes..."

[Rounin Ryuuji]

"Don't ask how the dishes got clean. You saw me, who always does the dishes, standing right there!"

That doesn't strike me as wrong, but it's not colloquial either. I'd say "me, the one who always does the dishes..."

I was thinking the same. I think it only loses the archaic flair if used with a proper name — "This person, (the one) who always does whatever thing, isn't doing it right now."

[hwhatting]

The West Germanic languages in general have a history of trading third person pronouns and demonstratives back and forth across part-of-speech classes, so I wouldn't be surprised if this behavior predates English as a separate language. Does anything screwey like this happen in German, say, in the usage of pronominal der vs. er?

In German, it also seems to be specifically es that cannot support a relative pronoun:
Ich, der immer den Müll rausträgt, soll faul sein? "I, the one who always takes out the trash, am supposed to be lazy?"
Du, der sonst immer am meisten quasselt, sagst jetzt gar nichts? "You, who normally always babbles the most, don't say anything now?"
Er, der die ganze Zeit geschwiegen hatte, begann zu sprechen. "He, who had been silent all the time, began to speak."
Er begann das Pferd zu streicheln. *Es, das bis dahin unruhig getänzelt hatte, wurde still und zutraulich. "He began to stroke the horse, *It, that had been prancing anxiously up to then, became quiet and tame."
Normally, you can replace es by a stressed das, but that would give the ugly Das, das, and the alternatives are hopelessly bookish / bureaucratese combinations like das, welches / dieses, das / dieses, welches, so the best solution would be to not use a relative sentence at all (e.g. Es hatte bisher unruhig getänzelt und wurde jetzt still und zutraulich.).
Pronouns followed by relative sentence referring to them are not as archaic as they seem to be in English, but still belong more to the literary register. What's totally archaic is the construction Pronoun, relative pronoun plus repeated pronoun that makes the verb in the relative sentence agree with the pronoun referred to, like Du, der du mein Liebster bist "*You, who you are my beloved". (Same for the construction with a non-pronoun antecedent, e.g. Vater unser, der du bist im Himmel from the Lord's Prayer - in contemporary German one would say Unser Vater, der im Himmel ist; modern versions of the prayer totally avoid the clumsy relative sentence and have Unser Vater im Himmel.)

[WeepingElf]

I wouldn't perceive Es, das ... as any less grammatical than Er, der ... or Sie, die .... Das, das ... sounds awkward, but so do Der, der ... and Die, die ....

[vegfarandi]

Icelandic relative clauses are quite different in general because there's no relative pronoun, only a relative particle sem, which doesn't show case, and therefore genitives and obliques can't be relativized. But it doesn't like relativizing personal (locuphoric) pronouns either. This sounds very strange – perhaps possible as a joke:

ég sem keypti ísinn á rétt á stærri skammti 'I who bought the ice cream have a right to a larger portion'

A more natural version involves clefting (I believe?):

það var ég sem keypti ísinn þannig ég á rétt á stærri skammti 'it was me (I) who bought the ice cream so I have a right to a larger portion'

In the third person, the demonstrative sá/sú/það has to be used:

sá sem startaði Zoominu getur mjútað hina 'he who/whoever/the one who initiated the Zoom call can mute the others'

The neuter það is incidentally identical to the personal pronoun for the same and thus can be used where English it and German es cannot:

það sem kvakar eins og önd hlýtur að vera önd 'that which quacks like a duck must be a duck'
það sem ég keypti í búðinni mega allir borða 'that which I bought in the sotre everyone can eat'

[cedh]

The West Germanic languages in general have a history of trading third person pronouns and demonstratives back and forth across part-of-speech classes, so I wouldn't be surprised if this behavior predates English as a separate language. Does anything screwey like this happen in German, say, in the usage of pronominal der vs. er?

For me, der / die / das (typically described as demonstratives) are actually the default 3rd person pronouns in most non-formal oral speech situations, with er / sie / es typically only appearing as clitics [=ɐ / =zə / =s] in immediate post-verbal position (and even there, der / die / das are used when the referent receives even a small amount of focus). That's not an extremely widespread phenomenon though; a friend of mine routinely mocks me whenever I refer to her by die rather than sie

I wouldn't perceive Es, das ... as any less grammatical than Er, der ... or Sie, die .... Das, das ... sounds awkward, but so do Der, der ... and Die, die ....

Der / die / das can all easily take a relative clause, although in case of a neuter antecedent, the relative pronoun is often was rather than das IML. (And of course, southwestern varieties of German generally use wo as a relative pronoun anyway. But I don't speak this way, even though I've been living in wo-territory for almost ten years now.)

[WeepingElf]

In my idiolect, der/die/das are the usual 3rd person pronouns, and I avoid the awkward der, der ...; die, die ...; das, das ... by using the old-fashioned relative pronouns welcher/welche/welches instead, so I get der, welcher ...; die, welche ...; das, welches .... Though I otherwise prefer the relative pronouns der/die/das.

[Linguoboy]

In my idiolect, der/die/das are the usual 3rd person pronouns, and I avoid the awkward der, der ...; die, die ...; das, das ... by using the old-fashioned relative pronouns welcher/welche/welches instead, so I get der, welcher ...; die, welche ...; das, welches .... Though I otherwise prefer the relative pronouns der/die/das.

How many repetitions of die can you get in a row? I can almost wrangle four, but that requires putting the colloquial personal pronoun die together with a definite pre-noun insert, which is kind of jarring stylistically.

[Imralu]

How many repetitions of die can you get in a row? I can almost wrangle four, but that requires putting the colloquial personal pronoun die together with a definite pre-noun insert, which is kind of jarring stylistically.

Ist die die, die die die Ballontiere, die bei der Party waren, gemacht habenden Clowns bezahlt hat?
That is not at all stylistically jarring. Not at all!

[hwhatting]

I wouldn't perceive Es, das ... as any less grammatical than Er, der ... or Sie, die .... Das, das ... sounds awkward, but so do Der, der ... and Die, die ....

Well, Es, das isn't strictly ungrammatical, but it implies a stressed es, which sounds very artificial to me - different to cedh or you, I do use er & sie as stressed pronouns, but I have es only as unstressed pronoun.

For me, der / die / das (typically described as demonstratives) are actually the default 3rd person pronouns in most non-formal oral speech situations, with er / sie / es typically only appearing as clitics [=ɐ / =zə / =s] in immediate post-verbal position (and even there, der / die / das are used when the referent receives even a small amount of focus). That's not an extremely widespread phenomenon though; a friend of mine routinely mocks me whenever I refer to her by die rather than sie

Yes, in general, using der, die, das as stressed pronouns is quite normal in colloquial German, although the distribution you have with them as default looks extreme to me. The distribution I have is more restricted; it's difficult to describe the rules. In any case it's still avoided in more formal and written registers; I still was taught that it's rude (I'm about 20 years older than you, IIRC), and there are (probably mostly older) people who may get offended if referred to by der or die.

In my idiolect, der/die/das are the usual 3rd person pronouns,

So you'd say something like Mein Chef geht mir auf die Nerven! Der will schon wieder eine Änderung an meiner Präsentation! Alle halbe Stunde kommt der mit einer neuen Anforderung or Ist mir egal was der will, sag dem, der soll mich am Arsch lecken?
I could imagine saying the first one, with der being emotional/expressive, but in the second example I'd use der only in the first occurrence and would have ihm / er in the following positions.

and I avoid the awkward der, der ...; die, die ...; das, das ... by using the old-fashioned relative pronouns welcher/welche/welches instead, so I get der, welcher ...; die, welche ...; das, welches .... Though I otherwise prefer the relative pronouns der/die/das.

Using der, welcher instead of er, der sounds absolutely jarring to me, as it is a combination of a very colloquial pronoun with a very bookish relative pronoun,

Ist die die, die die die Ballontiere, die bei der Party waren*1), gemacht habenden Clowns bezahlt hat?
That is not at all stylistically jarring. Not at all!

Yes, that's a bit much, due to the combination of colloquial pronoun use with an extremely bookish participle construction and Schachtelsatz, but four in a row (Ist die die, die die Clowns bezahlt hat?) is something you can find in real life speech.
*1) That sounds as if the ballon animals were guests at the party; I'd say something like die auf der Party verwendet wurden.