Changing Valency

[Benturi]

I was also wondering if it shouldn't be something like Il sont venus deux enfants. I don't remember having seen these constructions before, but my French is very rusty.

These are valid German sentences, however:

• Es sind viele Studenten gekommen.
  it be.3PL many students come.PP
  "Many students have come."
  
  Es bleiben vier Kandidaten.
  it remain.3PL four candidates
  "Four candidates remain."

As Zompist said about the French sentences, the subject ("many students", "four candidates") is detopicalized. Notice that "es" appears in the subject position, right before the verb, but the verb is in the 3PL form, agreeing with "students" or "candidates". I'd say there is no valency change here, and "es" only appears so that the verb occupies its usual second position.

[Ser]

• Il est venu deux enfants.
  il is.3SG come.SG two children
  'Three children came.'
  
  Il est monté trois voitures.
  il is.3SG gone.up.SG three cars.
  'Three cars went up.'

Those are not valid French sentences to me. I can only think of "Il est venu le temps de..." as being similar and correct.

Hmm... I guess I must be misremembering something about how this is formed, specifically about NPs defined by/beginning with numbers. The transformation is certainly possible and natural for rester at least:

• Trois jours restent encore.
  Il reste encore trois jours.
  'Three days still remain. ~ There's still three days.'

It is possible to find examples on google with venir, but I don't know how natural these might be (regardless of what or where I search for them, they're always very very few anyway).

• Joseph, à Charlotte. — Dites donc, la petite, est-ce vrai ce qu’on m’a dit en bas, qu’il est venu deux gendarmes pour arrêter monsieur ? (Georges Feydeau (1862-1921), Champignon malgré lui)

I bet there are quite a number of constraints regarding this, being specific to some particular intransitive verbs, maybe with different degrees of acceptance depending on definiteness (les and numbers being unfavored in contrast to des?). Maybe the plural itself is disfavoured in contrast to the singular (il est venu le temps de...). But the transformation exists.

• Il arrive des moments dans la vie où on peut se passer de choses qui nous semblaient capitales auparavant parce qu'on trouve une... (Journal de Montréal, 2013/07/23)

[RTLPM]

These are OK, even your very first one with the kids if we strain its meaning. But the one with "monter" is absolutely wrong. I can't find a rule myself though... You also have to consider that Feydeau's quote is old-fashioned.

[Chagen]

Causatives count as changing valency, right?

Sanskrit frequently uses causatives not for literal "X makes Y Z" sentences but just to distinguish transitivity and intransitivity:

vṛkṣ-aḥ

tree-NOM.SG

roh-a-ti

grow-3SG

A tree grows

vṛkṣ-am

tree-ACC.SG

rop-aya-ti

grow-CAUS-3SG

(He) grows a tree

You have to use the causative if the sentence is transitive. Frequently the causative has some distinctive meaning as well:

bodh-a-mi

learn-1SG

I learn

bodh-aya-mi

learn-CAUS-1SG

I inform

Some verbs ONLY appear in the causative, like ṛ (yes, just "ṛ") "transfer, hand over", which forms the verb arpayati, or spṛḥ "desire" which makes spṛḥayati

[Yaali Annar]

Causatives count as changing valency, right?
Sanskrit frequently uses causatives not for literal "X makes Y Z" sentences but just to distinguish transitivity and intransitivity:

vṛkṣ-aḥ

tree-NOM.SG

roh-a-ti

grow-3SG

A tree grows

vṛkṣ-am

tree-ACC.SG

rop-aya-ti

grow-CAUS-3SG

(He) grows a tree

[He] makes [the tree] [grow]

bodh-a-mi

learn-1SG

I learn

bodh-aya-mi

learn-CAUS-1SG

I inform

make [someone] [learn]

[Drydic]

Sanskrit frequently uses causatives not for literal "X makes Y Z" sentences but just to distinguish transitivity and intransitivity

As Yaali pointed out, there's no difference between making an intransitive transitive and making it causative.

[vec]

Well, a language can make such a distinction. I do remember reading about a natlang that treated all causers as instrumental case, though I'm not sure which one. My conlang Imuthan also treats causer arguments differently from agent arguments. Causatives are oblique case, agents are direct case. The morphological component rules – a causative suffix on an intransitive verb will trigger oblique subjects, while a transitive suffix triggers the direct.

Icelandic has weak-strong verb couplets where the weak ones are called causative verbs (orsakarsagnir) and the strong verbs are all intransitive:

brenna, brann, brunnum, brunnið "to burn (intr.)"
brenna, brenndi, brennt "to burn (tr.)"

ASFAIK these causative weak verbs are derived from PIE causatives.

[Drydic]

I'm not saying you're wrong, but if a language throws around banners and shouts THERE'S A DIFFERENCE!!!~~~ it's worth investigating whether or not there actually is a difference in meaning, or just two (or however many) ways of marking the same thing.