Learn Hardcore Swedish: Den blyga studenten skämtar bara med sin bästa vän. - The shy student only jokes with her best friend.

So when you say den … studenten (the student), the adjective blyg must change to blyga to agree with the definite noun. Using den blyg student is ungrammatical in standard Swedish.

Why do we need den when studenten is already definite?

Swedish uses “double definiteness” with adjectives: you mark definiteness both with a determiner (den/det/de) and with the definite ending on the noun (-en, -et, -na).

Pattern:

en student – a student
studenten – the student
den blyga studenten – the shy student

So when an adjective comes before a definite noun, you normally must add den/det/de.

Why is it den and not det blyga studenten?

Because student is an en-word (common gender), not an ett-word (neuter).

Common gender (en-words) → den in the singular: den här studenten
Neuter (ett-words) → det in the singular: det här huset

Since it’s en student, the correct form is den blyga studenten, never det blyga studenten.

Could we say En blyg student skämtar bara med sin bästa vän instead? What would change?

Yes, that sentence is grammatically correct, but the meaning changes slightly:

Den blyga studenten … = a specific student that speaker and listener can identify (“the shy student”).
En blyg student … = some shy student, not a particular one, more like “a shy student” in general.

So den makes it about a known, specific person; en makes it more generic or introduces a new character.

Why is the verb skämtar and not something like skämtarS for “he/she jokes”?

Swedish verbs do not change depending on the subject. There is one present tense form for all persons:

jag skämtar – I joke / I am joking
du skämtar – you joke
han/hon skämtar – he/she jokes
vi skämtar – we joke
ni skämtar – you (pl.) joke
de skämtar – they joke

So skämtar already covers “jokes” and “is joking”; there is no extra -s like in English he jokes.

Does skämtar mean “jokes” or “is joking”? How do you express the difference?

Skämtar can mean both “jokes” and “is joking.” Swedish doesn’t have a separate continuous form (is joking) like English. Context decides whether it’s habitual or happening right now:

Habitual: Den blyga studenten skämtar bara med sin bästa vän.
→ “The shy student only jokes with his/her best friend (in general).”
Right now: Tyst! Studenten skämtar bara med sin bästa vän.
→ “Quiet! The student is just joking with their best friend.”

Swedish uses adverbs, time expressions, or context instead of a special -ing form.

What exactly does bara mean here, and why is it placed after skämtar?

Bara here means “only” (and sometimes can be understood as “just”). In standard word order, Swedish often puts adverbs like bara after the verb in a main clause:

Subject – Verb – Adverb – Rest
Den blyga studenten – skämtar – bara – med sin bästa vän.

So bara limits the action skämtar: the student only jokes (and not something else), and does so only with that person. Different placements can change the focus slightly, e.g.:

Den blyga studenten bara skämtar med sin bästa vän.
→ More like “The shy student just jokes with his/her best friend (and doesn’t do anything serious).”

Why is it med sin bästa vän and not something like till sin bästa vän?

The verb skämta typically takes med when you talk about the person you’re joking with:

skämta med någon – joke with someone, kid around with someone
skämta om något – joke about something

So:

skämtar bara *med sin bästa vän = only jokes *with his/her best friend
Using till (skämta till någon) would be unidiomatic in this context.

Why is it sin bästa vän and not hans or hennes bästa vän?

Sin is the reflexive possessive pronoun for third person. It is used when the owner is the subject of the clause.

Here, den blyga studenten is the subject and also the one who has the best friend, so Swedish requires sin:

Den blyga studenten skämtar bara med *sin bästa vän.
→ He/she jokes with *his/her own best friend.

If you used hans or hennes, it would normally mean someone else’s best friend:

Den blyga studenten skämtar bara med *hans bästa vän.
→ The shy student jokes only with *his best friend (some other male person’s friend).

How can sin mean both “his” and “her”? Isn’t that ambiguous?

Yes, sin is gender‑neutral in Swedish: it can mean his, her, or their (singular), depending on who the subject is.

If the subject is a man, sin = “his”
If the subject is a woman, sin = “her”
If the subject’s gender is unknown/irrelevant, sin = “his/her” or “their” (singular)

Native speakers usually know from context who is being talked about, so it’s not ambiguous to them. In translation, we often write “his/her” or use singular they.

Why is it sin bästa vän and not sin bästa vännen?

With possessive pronouns like min, din, sin, vår, er, deras, Swedish normally uses the indefinite form of the noun, without the -en/-et/-na definite ending.

Compare:

vännen – the friend
min vän – my friend (not min vännen)
sin bästa vän – his/her best friend (not sin bästa vännen)

You don’t stack both a possessive and a definite ending on the same noun. So sin bästa vän is correct; sin bästa vännen is wrong.

Why is it bästa vän and not bäst vän?

Bäst is the basic superlative form (“best”) used mainly when the adjective stands alone or after vara (“to be”):

Hon är *bäst.* – She is best.

When the superlative adjective stands in front of a noun (attributive use), it usually takes -a:

min *bästa vän* – my best friend
den *bästa boken* – the best book

So before vän, you must say bästa. That’s why it’s sin bästa vän.

What are the genders of student and vän, and how do they affect the forms here?

Both student and vän are en-words (common gender):

en student → studenten (the student)
en vän → vännen (the friend)

This affects:

The choice of den (not det) in den blyga studenten.
The adjective endings in the indefinite: en blyg student, en god vän (no -t).

In the sentence, you see:

den for the definite en-word student
blyga for the definite form before studenten
vän left indefinite because it’s possessed by sin and Swedish avoids double definiteness there.