Learn Hardcore German: Mein Bruder fährt jetzt mit einem umweltfreundlichen Roller zur Arbeit und wirkt viel lockerer. - My brother now goes to work on an eco‑friendly scooter and seems much more relaxed.

fahren = to go/travel using a vehicle (car, bus, bike, scooter, etc.)
- Mein Bruder fährt mit dem Roller zur Arbeit.
  = He goes to work by scooter.
gehen = to go on foot (to walk)
- Mein Bruder geht zu Fuß zur Arbeit.
  = He walks to work.

Fahrt (with a) is:

ihr fahrt (you [plural] drive/go), or
the noun die Fahrt (the trip, the journey).

In this sentence, only fährt fits grammatically and semantically.

Why is it mit einem Roller and not auf einem Roller for “by scooter”?

In German, the usual way to say “by [means of transport]” is:

mit + dative + [vehicle]

Examples:

mit dem Auto – by car
mit dem Bus – by bus
mit dem Fahrrad – by bike
mit einem Roller – by scooter

So mit einem Roller = by scooter / using a scooter as transport.

Auf einem Roller literally means “on a scooter” and focuses on the physical position (standing/sitting on it), not the means of transportation as such. You might use auf if you really want to stress the position, for example:

Er steht auf einem Roller. – He is standing on a scooter.

But for “He goes to work by scooter”, German very naturally uses mit einem Roller.

Why is it einem umweltfreundlichen Roller? What’s going on with the article and the adjective ending?

The form einem umweltfreundlichen Roller is determined by:

The preposition mit
→ mit always takes the dative case.
The noun Roller
- Roller is masculine: der Roller.
- Dative masculine singular with ein = einem.
The adjective umweltfreundlich in front of a noun in the dative masculine with an indefinite article gets the ending -en.

So the full pattern is:

Nominative: ein umweltfreundlicher Roller (a green / eco-friendly scooter)
Accusative: einen umweltfreundlichen Roller
Dative: einem umweltfreundlichen Roller
Genitive: eines umweltfreundlichen Rollers

Because of mit (dative), you must say:

mit einem umweltfreundlichen Roller

Could we also say mit dem umweltfreundlichen Roller? What is the difference from mit einem umweltfreundlichen Roller?

Yes, both are correct, but they mean slightly different things:

mit einem umweltfreundlichen Roller
= with an eco-friendly scooter – any such scooter, not specified which one. It’s indefinite.
mit dem umweltfreundlichen Roller
= with the eco-friendly scooter – a specific scooter that is already known from context (for example, “the one he bought last month”).

In both cases, the grammar is:

mit → dative
Masculine dative singular with dem/einem
Adjective ending -en: umweltfreundlichen

Why is it zur Arbeit and not zu Arbeit?

Zur is a contracted form of zu der:

zu (to) + der (feminine dative article) → zur

The noun Arbeit (work) is feminine:

Nominative: die Arbeit
Dative: der Arbeit

After zu, you need dative, so:

zu der Arbeit → normally contracted to zur Arbeit

You generally cannot say zu Arbeit in this meaning. The idiomatic phrase in German is:

zur Arbeit fahren / gehen – to go to work

So zur Arbeit is both grammatically correct (zu + dative) and idiomatic.

Is there a difference between zur Arbeit fahren and zur Arbeit gehen?

Yes:

zur Arbeit fahren = to go/commute to work by some vehicle (car, bus, bike, scooter, etc.).
zur Arbeit gehen = to go/commute to work on foot (to walk).

In both cases, the destination phrase zur Arbeit stays the same. The verb tells you how he gets there:

Er fährt zur Arbeit. – He goes to work by some form of transport.
Er geht zur Arbeit. – He goes to work on foot.

What does wirkt mean here, and how is it different from arbeitet or funktioniert?

In this sentence, wirkt comes from wirken and means:

wirken = to seem, to appear, to come across as

So:

… und wirkt viel lockerer.
= “…and he seems / appears much more relaxed.”

This is different from:

arbeiten = to work (to do a job)
- Er arbeitet viel. – He works a lot.
funktionieren = to function, to work (for machines, systems)
- Der Roller funktioniert gut. – The scooter works well.

So:

Er wirkt lockerer. – He seems more relaxed (that’s the impression he gives).
Er arbeitet lockerer. – He works in a more relaxed way (his working style).
Der Roller wirkt – usually odd unless you mean “has an effect” in a special context; funktioniert is standard for machines.

Why is it wirkt viel lockerer and not ist viel lockerer? Is there a difference?

Both are possible, but they have slightly different nuances:

ist viel lockerer
= is much more relaxed – states a fact about his condition or personality.
wirkt viel lockerer
= seems/comes across much more relaxed – focuses on how he appears to others, the impression he gives.

In everyday conversation, wirkt is often used when you’re describing your subjective impression:

Seit er den Roller hat, wirkt er viel lockerer.
= Since he got the scooter, he seems much more relaxed (to me/us).

How is lockerer formed, and what is the base adjective?

The base adjective is locker (relaxed, loose, easy-going).

To form the comparative of most German adjectives, you add -er:

locker → lockerer (more relaxed)
schnell → schneller (faster)
laut → lauter (louder)

So:

viel lockerer = much more relaxed

If you compare explicitly:

Er wirkt lockerer als früher.
= He seems more relaxed than before.

What is the function of viel before lockerer?

Viel here is an intensifier. It strengthens the comparative:

lockerer = more relaxed
viel lockerer = much more relaxed / a lot more relaxed

Other intensifiers often used with comparatives:

ein bisschen lockerer – a bit more relaxed
deutlich lockerer – noticeably more relaxed
viel lockerer – much more relaxed

Why is jetzt placed after fährt and not like Mein Bruder jetzt fährt …? How does word order work here?

German main clauses follow the verb-second (V2) rule:

The finite verb (here: fährt) must be the second element in the main clause.

In:

Mein Bruder fährt jetzt mit einem umweltfreundlichen Roller zur Arbeit…

The structure is:

Mein Bruder – first element (subject)
fährt – second element (finite verb)
jetzt … – the rest of the sentence (the “middle field”)

So Mein Bruder fährt jetzt … is correct.

Mein Bruder jetzt fährt … would break the V2 rule, because then fährt would no longer be the second element.

You can move jetzt if you also move the first element appropriately, for example:

Jetzt fährt mein Bruder mit einem umweltfreundlichen Roller zur Arbeit…
Here, Jetzt is the first element, fährt is still second.

Can we move parts of the sentence around, like Jetzt fährt mein Bruder …? Does that change the meaning?

Yes, German allows you to move elements around for emphasis, as long as the finite verb stays in second position in a main clause.

Some natural variants:

Mein Bruder fährt jetzt mit einem umweltfreundlichen Roller zur Arbeit und wirkt viel lockerer.
– Neutral emphasis; subject first.
Jetzt fährt mein Bruder mit einem umweltfreundlichen Roller zur Arbeit und wirkt viel lockerer.
– Emphasizes the time aspect (“Now he goes by scooter…”).
Mit einem umweltfreundlichen Roller fährt mein Bruder jetzt zur Arbeit und wirkt viel lockerer.
– Emphasizes the means of transport (the eco-friendly scooter).

The basic meaning stays the same; what changes is what you highlight in the sentence. The key rule you must keep:

In a main clause, the conjugated verb (fährt, wirkt) must be in second position.