Learn Hardcore German: In meinem Sprachkurs sitzen eine Anfängerin und eine Fortgeschrittene zufällig nebeneinander. - In my language course a female beginner and a female advanced learner happen to sit next to each other.

Sprachkurs is masculine: der Sprachkurs
Masculine dative singular: dem Sprachkurs
With a possessive: mein behaves like an article and takes the dative ending:
- mein → meinem (masc./neut. dative singular)

So we get: in meinem Sprachkurs = “in my language course (class)”.

Why is the verb „sitzen“ used instead of „sind“?

German prefers a specific “position verb” where English often uses to be:

sitzen = “to be sitting / be seated”
stehen = “to be standing”
liegen = “to be lying”

In English you can say:

In my language course, a beginner and an advanced student *are next to each other.*

In German, it’s more natural to use sitzen because we’re talking about people in seats:

In meinem Sprachkurs sitzen … nebeneinander. = They are (sitting) next to each other.

You could say … sind nebeneinander, but it sounds odd for people in a classroom context. Sitzen is the idiomatic choice.

Why does the verb come right after „In meinem Sprachkurs“? Shouldn’t the subject come first?

German main clauses are verb-second (V2), not necessarily subject-first.

Rule: The conjugated verb must be in second position in the sentence. The first position can be many things: a subject, an adverb, a prepositional phrase, etc.

Here:

In meinem Sprachkurs → first position (prepositional phrase)
sitzen → second position (conjugated verb)
eine Anfängerin und eine Fortgeschrittene → subject (comes after the verb)
zufällig nebeneinander → adverbials (manner + place)

So the structure is:

[In meinem Sprachkurs] [sitzen] [eine Anfängerin und eine Fortgeschrittene] [zufällig nebeneinander].

If you start with the subject instead, the verb is still second:

Eine Anfängerin und eine Fortgeschrittene sitzen in meinem Sprachkurs zufällig nebeneinander.

Why are „eine Anfängerin“ and „eine Fortgeschrittene“ in the nominative case, even though they are not at the beginning?

Case in German is about function, not position.

The subject of the sentence is in the nominative case, no matter where it appears.

Here, who is doing the action sitzen (sit)?
→ eine Anfängerin und eine Fortgeschrittene.
That means they are the subjects, so they are nominative:

eine Anfängerin (feminine nominative singular)
eine Fortgeschrittene (feminine nominative singular)

The fact that they come after the verb doesn’t change the case; word order is flexible, case is determined by grammar roles.

Why is the verb „sitzen“ plural, even though we have „eine Anfängerin“ and „eine Fortgeschrittene“ with eine (singular)?

German (like English) agrees the verb with the entire subject, not with each part individually.

The subject here is a coordination of two singular nouns:

eine Anfängerin (one person)
und eine Fortgeschrittene (another person)

Together they form a plural subject:

eine Anfängerin und eine Fortgeschrittene → “a beginner and an advanced (student)” → they

So the verb must be plural:

… sitzen … (“are sitting”), not sitzt (“is sitting”).

Compare:

Eine Anfängerin sitzt … (singular)
Eine Anfängerin und eine Fortgeschrittene sitzen … (plural, two people)

Why are both „Anfängerin“ and „Fortgeschrittene“ feminine? Could I use masculine forms?

Yes, there are masculine versions; the sentence just chooses feminine people.

der Anfänger → die Anfängerin (female beginner)
der Fortgeschrittene → die Fortgeschrittene (female advanced learner)

So the sentence describes specifically two women (or people who are grammatically treated as feminine).

If you wanted to talk about two men, you could say:

In meinem Sprachkurs sitzen ein Anfänger und ein Fortgeschrittener zufällig nebeneinander.

For mixed or unspecified gender you might use:

ein Anfänger und eine Fortgeschrittene
or a gender-neutral formulation like eine Person mit wenig Erfahrung und eine mit viel Erfahrung, etc.

The original sentence simply picks feminine forms; that’s a content choice, not a grammar requirement.

What exactly is „Fortgeschrittene“? Is it an adjective or a noun, and why is it capitalized and ending in -e?

Fortgeschritten is originally an adjective/participle meaning “advanced” (literally “gone ahead”).

In eine Fortgeschrittene, this adjective is turned into a noun (nominalized adjective). German does this a lot:

ein Bekannter = a male acquaintance (from bekannt)
eine Angestellte = a female employee (from angestellt)
die Alte = the old woman (from alt, colloquial)

When an adjective is used as a noun:

It is capitalized: Fortgeschrittene
It takes adjective endings according to gender, case, and article.

Here:

Article: eine (indefinite, feminine, nominative singular)
Pattern: like eine schöne Frau
- schöne → Fortgeschrittene

So:

eine schöne Frau
eine Fortgeschrittene (literally “an advanced (female one)”)

Why is the adverb „zufällig“ placed before „nebeneinander“? Could I say „nebeneinander zufällig“?

Both zufällig nebeneinander and nebeneinander zufällig are grammatically possible, but they sound different.

zufällig = “by chance”, “coincidentally” (manner)
nebeneinander = “next to each other” (place)

A common tendency in German is:

Manner (how?)
Place (where?)

So zufällig nebeneinander fits that pattern well:

… sitzen zufällig nebeneinander. = They happen to be sitting next to each other.

nebeneinander zufällig sounds a bit more marked/odd and might be understood as:

They are next to each other, and that is what is random (emphasis on their being next to each other as the coincidental part).

The standard, most natural version is exactly what the sentence uses:

zufällig nebeneinander.

Why is „nebeneinander“ one word and not „neben einander“?

Nebeneinander is a fixed adverb meaning “(being) next to each other”.

Historically it comes from neben (“beside”) + einander (“each other”), but in modern standard German it’s written as one word in this meaning.

You normally write it together in expressions like:

nebeneinander sitzen – to sit next to each other
nebeneinander stehen – to stand next to each other
nebeneinander herlaufen – to walk alongside each other

„neben einander“ as two words is considered wrong spelling in standard German for this sense.

Could I also say „… sitzen zufällig nebeneinander“ instead of „… sitzen eine Anfängerin und eine Fortgeschrittene zufällig nebeneinander“? How flexible is the word order here?

You have quite a bit of flexibility; German word order is semi‑flexible. The sentence given is:

In meinem Sprachkurs sitzen eine Anfängerin und eine Fortgeschrittene zufällig nebeneinander.

Other natural variants include:

Move zufällig earlier:
- In meinem Sprachkurs sitzen zufällig eine Anfängerin und eine Fortgeschrittene nebeneinander. → Slightly stronger emphasis on the coincidence.
Start with the subject:
- Eine Anfängerin und eine Fortgeschrittene sitzen in meinem Sprachkurs zufällig nebeneinander.
Start with zufällig to really stress the coincidence:
- Zufällig sitzen in meinem Sprachkurs eine Anfängerin und eine Fortgeschrittene nebeneinander.

All of these are grammatical. What must remain is:

The finite verb (sitzen) in second position.
The other parts (subject, adverbs, prepositional phrases) may move around within the “middle field”, changing emphasis but not the basic meaning.