Ich spanne die Leine.

Because spanne is the 1st person singular present tense form of the verb spannen.

• ich spanne = I ...
• du spannst
• er/sie/es spannt
• wir spannen
• ihr spannt
• sie/Sie spannen

So -e is the normal ending for ich in the present tense.

The base form is spannen, which is the infinitive.

A helpful way to see it:

• infinitive: spannen
• verb stem: spann-
• ich form: spann- + -e = spanne

So Ich spanne ... literally uses the verb spannen in a conjugated form.

Because Leine is a feminine noun in German.

Its dictionary form is:

• die Leine

That means when you learn the noun, you should learn it together with its article: die Leine, not just Leine.

Yes, die Leine is the direct object, so it is in the accusative case. But in German, the feminine singular article die stays the same in both the nominative and accusative.

Compare:

• nominative: die Leine
• accusative: die Leine

Only masculine singular changes clearly in the accusative:

• nominative: der Hund
• accusative: den Hund

So die Leine is accusative here, even though the article still looks the same.

Because spannen is the action, and die Leine is the thing being affected by that action.

In Ich spanne die Leine:

• Ich = the subject, the person doing the action
• spanne = the verb
• die Leine = the direct object, what is being tightened/stretched

A useful question is: What am I tightening/stretching?
Answer: die Leine.

Leine can mean different things depending on context, such as:

• leash
• line
• rope
• cord

For example, it could refer to:

• a dog leash
• a rope or line being pulled tight
• a cord or strap

So the exact English word depends on the situation.

Not exactly. Spannen has the general idea of making something tight, taut, stretched, or under tension.

Depending on context, it can be translated as:

• to tighten
• to stretch
• to tension
• to pull taut

So the core idea is the same, but the best English translation changes with context.

This is the normal word order for a simple German main clause:

• subject + verb + object

So:

• Ich = subject
• spanne = verb
• die Leine = object

German also has an important rule: in a main clause, the finite verb usually comes in second position. That is true here.

Yes, you could, but it changes the emphasis.

• Ich spanne die Leine. = neutral statement
• Die Leine spanne ich. = emphasizes the line/leash

German allows different elements to come first for emphasis, but the conjugated verb still stays in second position:

• Die Leine | spanne | ich

So the second version is possible, just less neutral.

Because all German nouns are capitalized.

So:

• ich is not capitalized here because it is a pronoun, not a noun
• Leine is capitalized because it is a noun

This is one of the most noticeable spelling rules in German.

A simple pronunciation guide is:

• Ich ≈ ikh / ish depending on accent and what you are used to hearing
• spanne ≈ SHPAH-nuh
• die Leine ≈ dee LYE-nuh

A few key points:

• sp at the beginning of spanne sounds like shp in standard German
• ei in Leine sounds like English eye
• the final -e in spanne and Leine is usually a soft uh sound

It usually tells you that the vowel before it is short.

So in spanne, the a is short, not long.

Compare the idea:

• spannen → short a
• not like English spa, which has a long vowel sound

For learners, the main practical point is: say spanne with a short vowel.

Normally, no. In standard German, you usually need the subject pronoun.

So you say:

• Ich spanne die Leine.

Not normally:

• Spanne die Leine.

That shorter version would usually sound like an imperative:

• Spanne die Leine! = Tighten the line!

So including ich matters.