Quick conditionals question

[Emily]

are there any (natural) languages where, in conditional sentences, the condition and conclusion are linked by a conjunction but there's no corresponding "if" word at the beginning of the condition? so for example in english we say "if i get hungry, (then) i'll eat a cheeseburger", which can be thought of as

IF i get hungry
THEN i'll eat a cheeseburger

whereas what i'm looking for is more on the order of

i (will) get hungry IF/THEN i'll eat a cheeseburger

btw i'm specifically asking about this happening in sentences with the condition first, not an english-style inversion with the conditional second (so, not "i'll eat a cheeseburger if i get hungry"). hopefully i'm explaining clearly what i mean, sorry! thank you!

[alice]

I've done this in conlangs, but I don't know about natlangs, although there must be some.

[Nortaneous]

Unmarked protasis is permissible in Tocharian B.

In Adams's "Present Open Condition 1", in which the protasis and apodosis both appear in the present, the protasis is almost always marked by kwri ~ krᵤi unless the subject of the protasis is ksa "someone/anyone", and the apodosis may be marked with ot, but frequently isn't.

mā ks-allek ñke ñi plänkṣalle nesäṃ, ṣañ-añm pläṅksemar
NEG someone other.M.SG now 1SG.GEN be_sold-CAUS-GER COP.PRES-3SG | REFL-ACC be_sold-CAUS-1SG.MP
"[if] there is nothing to buy from me, I will sell myself" (Adams's translation, which is not terribly literal)

In "Present Open Condition 2", in which the protasis takes the subjunctive and the apodosis takes the present, Adams says that kwri is absent in about a third of cases. It's unclear what the semantic difference was between the two conditional constructions.

tū yairu tākaṃ, sū ceṃ ñakteṃne tänmasträ
3SG.N.DIR practice-??? COP.SBJV.3SG | 3SG.M.NOM 3PL.M.ACC god-PL.ACC-LOC be_born-3SG.MP
"[if] he has practiced that, he will be born among the gods"
(yairu here is some irregularly spelled form of wär "practice", probably an uninflected participial form yeyäru. ceṃ is either 3PL.M.ACC or the accusative of the (emphatic?) demonstrative seṃ "this", in the accusative case but unmarked for number. tänmasträ is unmarked for valence but in context is probably a Grundverb rather than a causative.)

There are various other conditional constructions, which, like Present Open Condition 2, typically take kwri but sometimes don't. (Cf. colloquial American English, where it's permissible but uncommon to form a conditional in which the protasis precedes the apodosis and takes the present simple and no conjunction, and the apodosis takes a future tense, e.g. "he goes in my room one more fuckin time imma kick his ass into the kuiper belt".)

This isn't a perfect example, though - Adams doesn't list any sentences in which kwri is omitted but ot is present, and since ot was apparently primarily used in Present Open Condition 1 (where kwri was almost obligatory unless the subject of the protasis was ksa), such sentences may not exist.

[Kuchigakatai]

are there any (natural) languages where, in conditional sentences, the condition and conclusion are linked by a conjunction but there's no corresponding "if" word at the beginning of the condition? so for example in english we say "if i get hungry, (then) i'll eat a cheeseburger", which can be thought of as

IF i get hungry
THEN i'll eat a cheeseburger

whereas what i'm looking for is more on the order of

i (will) get hungry IF/THEN i'll eat a cheeseburger

btw i'm specifically asking about this happening in sentences with the condition first, not an english-style inversion with the conditional second (so, not "i'll eat a cheeseburger if i get hungry"). hopefully i'm explaining clearly what i mean, sorry! thank you!

Yes, it's very common in Mandarin and Classical/Literary Chinese. Basically, "then" is used a lot of the time (I get hungry, then I('ll) eat a cheeseburger) (not that the pre-modern Chinese talked about cheeseburgers much). You can also have plain juxtaposition in both languages (I get hungry, I eat a cheeseburger), more commonly than in English too, and it is understood as a condition from context. Note that both languages also have words equivalent to English "if", but using "if" just happens to be optional...

[Vijay]

are there any (natural) languages where, in conditional sentences, the condition and conclusion are linked by a conjunction but there's no corresponding "if" word at the beginning of the condition?

Yes, Hindi/Urdu does exactly this! (EDIT: Well, you can use a word for 'if', but it's not usually done IME. The word for 'if' that appears to usually be listed in grammars at least is a loanword from Persian, and the only other one I know of normally has a different meaning).

It's even possible with scrambled word order:
[ˈɾuːʈʰɨ na ˈd͡ʒaːnaː t̪ʊmː se kəˈhũ t̪o]
"[mɛ̃ː ˈɪnɨ ˈãːkʰõː mẽː d͡ʒo ɾəˈhũ t̪o]?"!
I believe normal word order would be more like "[d͡ʒo mɛ̃ ɪn ˈãkʰõ mẽ ɾəˈhũ t̪o]?" [t̪ʊm se kəˈhũ t̪o ɾuʈʰ(ɨ) na ˈd͡ʒana]!

Apparently meaning roughly:
Don't get all mopey if I say to you,
"What if I lived in these eyes?"!

[zompist]

Here's an example from Old Chinese:

Jūnzǐ bú zhòng, zé bù wēi.
gentleman not weight then not prestige
If the gentleman has no graviry, he will have no prestige.

OC never does things in just one way, and an alternative construction is interesting: rú X zé Y, except that rú occurs in second position, after the subject.

[dɮ the phoneme]

Japanese has several ways of handling conditionals, none of which obligatorily use the word for 'if' (moshi), which is essentially just an ordinary adverb. In my experience, moshi is used to emphasize the counterfactual nature of an antecedent, but it's frequently omitted. One of the conditionals in Japanese is the post-verbal particle to, which is used for 'natural' or inevitable consequences:

haru ni naru to, sakura ga saku
spring DAT become.NPST COND, cherry.blossum NOM bloom.NPST
"When it becomes spring, the cherry blossoms will bloom" (impl.: naturally, as they always do)

I think this is exactly the type of construction you're looking for.

Japanese also uses other conditionals marked with verbal suffixes:

tōkyō ni ikeba tōkyō-tawā ga mitai
tōkyō ni ik-eba tōkyōtawā ga mi-tai
Tokyo DAT go-COND Tokyo Tower NOM see-want.NPST
"If I go to Tokyo, I'd like to see Tokyo Tower"

tōkyō ni ittara tōkyō-tawā ga mitai
tōkyō ni itta-ra tōkyōtawā ga mi-tai
Tokyo DAT go.PST-COND Tokyo Tower NOM see-want.NPST
"If I go to Tokyo, I'd like to see Tokyo Tower"

These have slightly different nuances, but both are general-purpose conditionals marked with an element (a suffix, in this case) between the antecedent and consequent.