Learn Hardcore German: Der Hund soll an der Leine bleiben, damit niemand verletzt werden kann. - The dog should stay on the leash so that nobody can get injured.

The verb sollen expresses a duty, rule, or expectation that usually comes from an external source (rules, authorities, other people), not from the speaker personally.

In this sentence, Der Hund soll an der Leine bleiben means roughly:

The dog is supposed to stay on the leash.
or: The dog should stay on the leash.

Nuances compared to other verbs:

müssen = must, have to (strong necessity, often absolute)
- Der Hund muss an der Leine bleiben.
  → The dog must stay on the leash. (no option)
sollen = is supposed to / should (rule, instruction, or expectation)
- Der Hund soll an der Leine bleiben.
  → According to the rules/what someone decided, the dog should stay on the leash.

So soll here does not sound like a personal recommendation; it sounds like a rule or requirement (for example, from the park regulations).

Why is the main verb bleiben at the end of the first part: Der Hund soll an der Leine bleiben?

German main clauses follow a verb-second (V2) rule for the finite verb (the conjugated verb).

In Der Hund soll an der Leine bleiben:

soll is the finite verb (the conjugated form of sollen),
bleiben is an infinitive (the full form of the lexical verb).

In a main clause with a modal verb (like sollen, können, müssen):

The finite verb (the modal, here soll) goes in second position.
The lexical verb in the infinitive (here bleiben) goes to the end of the clause.

Structure:

Der Hund – position 1 (subject)
soll – position 2 (finite verb)
an der Leine – middle field
bleiben – final position (infinitive)

Compare:

Without modal: Der Hund bleibt an der Leine.
With modal: Der Hund soll an der Leine bleiben.

Why is it an der Leine and not an die Leine?

The preposition an can take either dative or accusative, depending on whether it describes:

location (where?) → dative
direction / movement (where to?) → accusative

In this sentence:

Der Hund soll an der Leine bleiben
→ The dog should stay at/on the leash (location, no movement) → so an
- dative: an der Leine

If you talk about putting the dog on the leash (movement towards something), you use accusative:

Ich nehme den Hund an die Leine.
→ I put the dog on the leash. (direction, movement) → an
- accusative: an die Leine

So an der Leine = being at/on the leash (state),
an die Leine = moving to the leash / being put on the leash.

Why do we see der Leine, when the dictionary says the noun is die Leine?

The base form of the noun is indeed die Leine (feminine, nominative singular).

However, German articles change with case. After the preposition an, when it expresses location, you need the dative case:

Feminine article:
- Nominative: die Leine
- Accusative: die Leine
- Dative: der Leine

So:

die Leine (subject, basic dictionary form)
- Die Leine ist neu. – The leash is new.
an der Leine (after an with dative)
- Der Hund ist an der Leine. – The dog is on the leash.

That is why you see der Leine here: it is simply the dative form of die Leine.

What is the function of damit here, and how is it different from weil or deshalb?

damit introduces a purpose clause – it answers the question “for what purpose?” / “so that what happens?”.

In the sentence:

…, damit niemand verletzt werden kann.
→ … so that nobody can get hurt.

Important contrasts:

damit = so that / in order that (expresses purpose or intention)
- Der Hund soll an der Leine bleiben, damit niemand verletzt werden kann.
  → The dog should stay on the leash in order that nobody can be hurt.
weil = because (expresses reason)
- Der Hund soll an der Leine bleiben, weil sonst jemand verletzt werden kann.
  → The dog should stay on the leash because otherwise someone could get hurt.
deshalb / darum / daher = therefore, so (also express consequence, not purpose; they are adverbs, not conjunctions)
- Jemand könnte verletzt werden, deshalb soll der Hund an der Leine bleiben.
  → Someone could get hurt, therefore the dog should stay on the leash.

So damit is best translated as so that or in order that, and it always introduces a subordinate clause expressing an intended result.

Why is the word order niemand verletzt werden kann and not niemand kann verletzt werden?

Inside the damit-clause we are in a subordinate clause, and German subordinate clauses send the finite verb to the end.

Here the subordinate clause is:

damit niemand verletzt werden kann

Verb forms involved:

kann – finite verb (modal, from können)
werden – auxiliary verb for the passive
verletzt – past participle (from verletzen)

Rules:

In a main clause with modal + passive, the finite verb is second:
- Niemand kann verletzt werden.
In a subordinate clause, all verb parts go to the end, with the finite verb last:
- …, damit niemand verletzt werden kann.

The typical order in such verb clusters:

participle (verletzt)
auxiliary infinitive (werden)
finite modal (kann) at the very end

So niemand verletzt werden kann is exactly the normal subordinate-clause order.

Why does the sentence use a passive structure verletzt werden kann instead of something like sich verletzen kann?

verletzt werden kann is passive voice:

verletzt werden = to be injured / to get hurt
kann verletzt werden = can be injured / can get hurt

Passive is used here because the focus is on:

the affected person (any potential victim),
not on who or what causes the injury.

We don’t explicitly say “by the dog” in the sentence, but it is implied.

Compare:

Passive (used in the original):
- …, damit niemand verletzt werden kann.
  → so that nobody can be injured / get hurt.
Reflexive, active:
- …, damit sich niemand verletzen kann.
  → so that nobody can hurt themselves.

Both are possible, but:

verletzt werden feels more general and neutral: any kind of injury.
sich verletzen focuses on the person injuring themselves, which is slightly different in nuance.

In the context of a dog and safety rules, verletzt werden neatly expresses “be injured (by the dog or by an incident)” without saying exactly how.

What does niemand mean exactly? Is it singular or plural, and how does it differ from keiner?

niemand means nobody / no one.

Grammatically:

It is treated as singular.
The verb agrees in the 3rd person singular:
- Niemand kann verletzt werden. (not: können)

Difference to keiner:

niemand = nobody at all (people only)
keiner = no one / nobody, but behaves like a declined pronoun/adjective; it agrees in gender, case, and number.

Examples:

Niemand ist da. – Nobody is there.
Keiner ist da. – No one is there. (similar meaning)

niemand is slightly more neutral/formal. keiner can sound a bit more colloquial or personal in many contexts, but often they are interchangeable.

In the sentence:

…, damit niemand verletzt werden kann.

you could also hear:

…, damit keiner verletzt werden kann.

Both are correct; niemand is a bit more formal and clear for learners.

Can you replace niemand with keiner in this sentence? Would that change the meaning?

Yes, you can say:

Der Hund soll an der Leine bleiben, damit keiner verletzt werden kann.

The meaning is practically the same:

niemand – nobody
keiner – no one / nobody

Differences:

Style/feel:
- niemand feels a bit more neutral and slightly more formal.
- keiner is somewhat more colloquial in many contexts.
Precision:
- niemand is unambiguously only about people.
- keiner can, in other contexts, also refer to things (with appropriate gender), though here it clearly refers to people too.

In this concrete sentence, it is mostly a stylistic choice, not a difference in meaning.

Why is there a comma before damit?

In German, subordinate clauses must be separated from the main clause by a comma.

damit is a subordinating conjunction (like weil, dass, obwohl).
It introduces a subordinate clause (here: damit niemand verletzt werden kann).

So the structure is:

Main clause: Der Hund soll an der Leine bleiben,
Subordinate clause: damit niemand verletzt werden kann.

Rule:
Before conjunctions like dass, weil, wenn, obwohl, damit, you must put a comma.

Therefore, the comma before damit is obligatory, not optional.