Learn Hardcore Hausa: Lafiya tana da muhimmanci sosai.

Lafiya is grammatically feminine, so it takes ta‑ forms.
tana = ta (she/it, feminine) + na (continuous/aspect marker).
If the subject was a masculine noun, you would use yana:
Lafiya tana da muhimmanci sosai. – lafiya is feminine.
Littafi yana da muhimmanci sosai. – littafi (book) is masculine.

What does the whole phrase tana da mean here?

tana da is often best translated as has or possesses in this kind of sentence.
Literally:

tana – it (fem.) is (in a state of)
da – with / having
So lafiya tana da muhimmanci sosai is literally something like Health is with a lot of importance, i.e. Health has great importance → Health is very important.

What is the role of da in this sentence?

da is a very common word meaning with, and in many contexts it functions like have/has.
Pattern: [subject] + (ya/ta)na da + [thing] = [subject] has [thing].
Examples:

Ina da mota. – I have a car.
Suna da yara. – They have children.
In Lafiya tana da muhimmanci sosai, da links lafiya to muhimmanci, showing that health has importance.

What is the difference between muhimmanci and muhimmi?

muhimmi is an adjective: important.
muhimmanci is a noun: importance.

So:

Lafiya tana da muhimmanci sosai. – Health has a lot of importance / Health is very important.
You could also (more literally adjectival) say: Lafiya muhimmiyar ce sosai. – Health is very important.
In everyday speech, tana da muhimmanci is very natural and common.

Why is there no separate word for is like English is in this sentence?

Hausa often doesn’t use a standalone is the way English does.
Here, the function of is is built into the structure tana da – that whole unit carries the idea is/has.
If you wanted a more explicit is with an adjective, you could use ne/ce, e.g.:

Lafiya muhimmiyar ce. – Health is important.
But for has importance / is important, tana da muhimmanci is the normal pattern.

What does sosai mean, and can it go anywhere else in the sentence?

sosai means very, very much, extremely, really.
Placement: it usually comes after the word or phrase it is intensifying:

muhimmanci sosai – very important / a lot of importance.
You might also see it at the end of the sentence in speech, but the core idea is that it strengthens what comes just before it.

How would I say My health is very important using this pattern?

You add a possessive suffix to lafiya:

lafiya (health) → lafiyata (my health).

So:

Lafiyata tana da muhimmanci sosai. – My health is very important.

Is there a way to say I have health / I am healthy that also uses lafiya and da?

Yes. You can use the [pronoun] + na/ni/ka + da lafiya pattern for have health / be healthy.
Examples:

Ina da lafiya. – I am healthy / I am fine.
Kana da lafiya? – Are you healthy / Are you OK? (to a man)
This is different from Lafiya tana da muhimmanci sosai, which is a general statement about health, not your current state.

How do I make this sentence negative, like Health is not very important?

To negate tana da, you usually change it to ba ta da.
So:

Lafiya tana da muhimmanci sosai. – Health is very important.
Lafiya ba ta da muhimmanci sosai. – Health is not very important.

Pattern: [subject] + ba + (ya/ta) + da + [noun] → [subject] does not have [noun] / is not [noun] in this kind of structure.

Could lafiya also mean safety or peace here, or only health?

Lafiya’s core idea is being in a good, safe, unharmed state, so context decides the best English word.

In general statements like this, it most naturally means health or well‑being.
In other contexts it can lean toward safety or peace:
- Muna addu’ar lafiya. – We pray for safety / well‑being.
  So this sentence can be understood as Health / well‑being is very important.

How is lafiya pronounced and divided into syllables?

Lafiya has three syllables: la‑fi‑ya.
Approximate pronunciation: la as in la in lava, fi like fee, ya like ya in yard (but shorter).
Stress is usually on the first syllable: LÁ‑fi‑ya.