Learn Hardcore Finnish: Taksin kuljettaja on ystävällinen, ja hän auttaa kantamaan laukun. - The taxi driver is friendly, and she helps carry the bag.

taksin is genitive singular. In Finnish, a noun in the genitive can modify another noun to express an of-relationship: taksin kuljettaja = the taxi’s driver.
You can also write the profession as a compound: taksinkuljettaja. Compounds are very common for established roles and are often preferred in neutral writing. Both taksin kuljettaja and taksinkuljettaja are correct; the compound treats it as a fixed profession, the two-word version reads a bit more literally as the driver of the taxi (in this context, still the profession).

Why is there a comma before ja?

Finnish uses a comma between two independent clauses. Here, Taksin kuljettaja on ystävällinen and hän auttaa kantamaan laukun are both full clauses with their own subject and finite verb, so a comma before ja is standard. If the subject isn’t repeated (shared subject), you typically don’t use a comma:

With repeated subject: …, ja hän auttaa… → comma.
With shared subject: Taksin kuljettaja on ystävällinen ja auttaa kantamaan laukun. → no comma.

Does hän mean he or she? Can I use se?

hän is gender-neutral and covers both he and she.
In informal spoken Finnish, people often use se for humans too. In formal writing, stick to hän.

Could I omit hän in the second clause?

Yes. If the subject is the same as in the first clause, Finnish can drop it:

Taksin kuljettaja on ystävällinen ja auttaa kantamaan laukun. Omitting hän also changes the comma rule: with shared subject, no comma before ja.

What does on do here? Can it be left out?

on is the 3rd person singular of the verb to be (the copula). In standard written Finnish you include it: (Hän) on ystävällinen. In casual speech, especially with se, people sometimes drop it (e.g., Se ystävällinen), but that’s colloquial and not recommended in writing.

Why is it auttaa kantamaan and not auttaa kantaa?

After auttaa (to help), the canonical way to express helping to do something is the MA-infinitive in the illative: -maan/-mään. So you say:

auttaa + (someone) + V-mAAn → auttaa kantamaan, auttaa tekemään, auttaa siivoamaan. The form auttaa kantaa is not standard.

Why is laukun in that form? Why not laukku?

laukun is the total object (accusative-genitive form) of the verb kantaa (to carry) inside the non-finite clause kantamaan. It signals a bounded, complete carrying of the bag. Nominative laukku cannot be used as a direct object here.

When would I use laukkua instead of laukun?

Use laukkua (partitive object) when the action is unbounded/ongoing, incomplete, or otherwise not total:

hän auttaa kantamaan laukkua = he helps to carry the bag (for a while / partially / without implying completion). In negatives, the object is also partitive: hän ei auta kantamaan laukkua.

Who is being helped? How would I say He helps me carry the bag?

If you specify the person being helped, that person is in the partitive:

Hän auttaa minua kantamaan laukun. = He helps me carry the bag. This shows two things:
auttaa + person (partitive): auttaa minua/sinua/asiakasta.
The object of the embedded verb (kantaa) behaves as usual (laukun total vs laukkua partitive).

Is hän auttaa laukun kanssa a correct way to say he helps with the bag?

Not by itself. auttaa X:n kanssa means help someone with X:

Hän auttaa minua laukun kanssa. = He helps me with the bag. Saying auttaa laukun kanssa lacks the person being helped and sounds odd. To focus on the action, prefer auttaa kantamaan (laukkua/laukun).

Can I rephrase it as Ystävällinen taksinkuljettaja auttaa kantamaan laukun?

Yes. That compresses the information into one clause with an attributive adjective. It’s natural and common. Nuance:

Two-clause version highlights the friendliness as a separate statement.
One-clause version presents friendliness as a descriptive attribute of the driver doing the helping.

How do I say He helps carry his own bag vs the passenger’s bag?

Own bag (subject’s bag): Hän auttaa kantamaan laukkunsa. (possessive suffix -nsa/-nsä)
Passenger’s bag: Hän auttaa kantamaan asiakkaan laukun.

Why is ystävällinen in that form? Should it agree in case or number?

As a predicate adjective after olla (to be), ystävällinen is in nominative singular agreeing with a singular subject:

Kuljettaja on ystävällinen. With a plural subject: Kuljettajat ovat ystävällisiä (partitive plural predicative is typical after plural ovat).

How is kantamaan formed?

It’s the MA-infinitive, illative case (also called the third infinitive illative).

Take the verb stem and add -maan/-mään (vowel harmony).
Examples:
- kantaa → kantamaan
- tehdä → tekemään
- syödä → syömään
- opiskella → opiskelemaan

What sound change is happening in laukun compared to laukku?

Consonant gradation. The strong grade kk (in laukku, nominative) becomes the weak grade k in the genitive/accusative laukun. Many Finnish nouns show this alternation (e.g., patikka → patikan, täkki → täkin).

Is kuski okay instead of kuljettaja?

kuski is colloquial for driver, widely used in speech: taksikuski.
kuljettaja is the neutral/official term, preferred in formal or written contexts. Both are understood.