Learn Hardcore Hausa: Da ruwa ya ƙaru sosai, da ba mu iya tsallaka kogin ba. - If the water had risen a lot, we would not have been able to cross the river.

Here, da does not mean and/with (its other common meaning); it is specifically introducing a hypothetical condition in the past that did not actually happen.

Why is da used again before ba mu iya tsallaka kogin ba?

In Hausa unreal (counterfactual) conditionals about the past, da is usually placed:

at the start of the if-clause, and
at the start of the then-clause.

So the pattern is:

Da [past event that did not happen], da [past result that also did not happen].

In this sentence:

Da ruwa ya ƙaru sosai,
If the water had risen a lot,
da ba mu iya tsallaka kogin ba.
then we would not have been able to cross the river.

The second da links the imagined result to the imagined condition. It has no direct English word-for-word equivalent; it is part of the standard Hausa way of forming this type of conditional.

Is this talking about a real situation or a hypothetical / unreal one?

It is talking about an unreal, past situation – something that did not happen.

The structure da … da … with past forms (like ya ƙaru, ba mu iya) is typically used for:

counterfactual past:
If X had happened, Y would have happened (but in reality, X did not happen, so Y did not happen).

So the sentence means roughly:

The water did not actually rise that much,
and we did cross the river,
but the speaker is imagining a different past in which the water had risen, and in that imaginary past, they would not have been able to cross.

How would this sentence change if I wanted a real, future conditional instead of a counterfactual past?

For a real future situation (something that really might happen later), Hausa more often uses idan or in instead of da, and za for future ability:

Idan ruwa ya ƙaru sosai, ba za mu iya tsallaka kogin ba.
If the water rises a lot, we will not be able to cross the river.

Compare:

Da ruwa ya ƙaru sosai, da ba mu iya tsallaka kogin ba.
If the water had risen a lot, we would not have been able to cross the river. (unreal past)

vs.

Idan ruwa ya ƙaru sosai, ba za mu iya tsallaka kogin ba.
If the water rises a lot, we will not be able to cross the river. (real future possibility)

What exactly does ruwa ya ƙaru sosai mean grammatically?

Breakdown:

ruwa – water
ya – 3rd person masculine singular subject pronoun, perfective (past-like)
ƙaru – to increase, grow, rise (in amount/level)
sosai – very, a lot, greatly

So:

ruwa ya ƙaru sosai ≈ the water increased a lot / the water rose a lot.

Grammatically, ruwa is the subject, and ya is the required subject pronoun that shows person, gender, and aspect. Hausa normally uses this pronoun even when there is a full noun subject.

You cannot normally say ✗ ruwa ƙaru sosai; you need ya: ruwa ya ƙaru sosai.

Why is there a pronoun ya when we already have ruwa as the subject? Can it be left out?

In Hausa, finite verbs normally agree with their subject using a subject pronoun that also marks tense/aspect. This pronoun is required even if the subject noun is present.

So:

ruwa ya ƙaru – literally: water it.increased
(English does not do this, but Hausa does.)

You generally cannot omit ya in this kind of clause:

✔ Ruwa ya ƙaru sosai. – The water increased a lot.
✗ Ruwa ƙaru sosai. – Ungrammatical in normal speech.

The same pattern appears with other nouns:

Audu ya tafi. – Audu went.
Mota ta tsaya. – The car stopped.

ya / ta / suka / muka, etc., are an essential part of Hausa verbal grammar, not optional pronouns like in English.

What does sosai add, and where does it usually go?

sosai is an adverb of degree meaning very, greatly, a lot, extremely.

In ruwa ya ƙaru sosai, it modifies the verb ƙaru, telling us how much the water increased: it increased a lot / very much.

Position:

It usually comes after the verb or verb phrase it modifies:
- ya gaji sosai – he is very tired
- sun yi aiki sosai – they worked a lot
- ruwa ya ƙaru sosai – the water increased a lot

You generally would not place sosai before the verb in this kind of sentence.

Why is it kogin and not just kogi?

kogi means river (indefinite, like a river).
kogin is kogi
- the definite suffix -n, roughly the river.

So:

tsallaka kogi – to cross a river (unspecified)
tsallaka kogin – to cross the river (a specific one already known from context)

In the sentence, kogin suggests a specific river the speaker has in mind (for example, the river they were actually crossing).

How does the negation ba mu iya tsallaka kogin ba work?

This is the standard ba … ba clausal negation in Hausa.

Breakdown:

ba – first negative particle (comes at the start of the clause)
mu – 1st person plural subject pronoun (we)
iya – be able, have the ability
tsallaka – to cross, to jump across
kogin – the river
ba – closing negative particle (at the end of the clause)

So:

ba mu iya tsallaka kogin ba ≈ we could not cross the river / we were not able to cross the river.

The pattern is:

ba
- subject + verb (+ object) + ba

Examples:

ba mu je ba – we did not go
ba ta gani ba – she did not see
ba su sayi littafi ba – they did not buy a book

Here, iya acts like the main verb: ba mu iya (tsallaka kogin) ba.

What is the nuance of iya in this sentence? Is it like English “can”?

iya expresses ability or capability, similar to English can / be able to.

In ba mu iya tsallaka kogin ba, it means we were not able / we could not.

Some points:

It usually takes a following verb (an action) that you are able or unable to do:
- zan iya yin hakan – I will be able to do that
- ba ta iya karatu ba – she cannot read / she does not know how to read
In this sentence, tsallaka kogin is the action whose possibility is being denied:
- mu iya tsallaka kogin – we can/could cross the river
- ba mu iya tsallaka kogin ba – we cannot/could not cross the river

In the counterfactual context created by da … da …, the natural English translation is would not have been able to, even though Hausa just uses iya with the negative.

Could I say ba za mu iya tsallaka kogin ba instead, and how would that change the meaning?

Yes, you can say:

ba za mu iya tsallaka kogin ba – we will not be able to cross the river / we would not be able to cross the river

The difference is:

ba mu iya tsallaka kogin ba (as in the original sentence) is a past-like ability:
we could not / we were not able (within the imagined past).
ba za mu iya tsallaka kogin ba is future or hypothetical ability:
we will not be able / we would not be able (looking forward from some point in time).

So:

Da ruwa ya ƙaru sosai, da ba mu iya tsallaka kogin ba.
If the water had risen a lot, we would not have been able to cross the river. (unreal past)
Da ruwa ya ƙaru sosai, da ba za mu iya tsallaka kogin ba.
If the water rose a lot, we would not be able to cross the river. (unreal present/future; less clearly tied to the past)

Can the order tsallaka kogin be changed, or must the verb come before the object?

In Hausa, the normal order in a simple clause is:

Subject – Verb – Object

So:

mu iya tsallaka kogin
we be-able-to cross the-river

Verb phrase:

tsallaka – verb
kogin – its object

You do not normally move the object in front of the verb:

✔ tsallaka kogin – cross the river
✗ kogin tsallaka – ungrammatical in this meaning

So in this sentence, the order tsallaka kogin is the standard and expected one.