يشعل صديقي نار المخيم خلال الليل.

Because Arabic very often uses verb–subject–object order, especially in straightforward statements.

So this sentence breaks down as:

• يشعل = lights / is lighting
• صديقي = my friend
• نار المخيم = the campfire / the fire of the camp
• خلال الليل = during the night

So the pattern is:

• verb: يشعل
• subject: صديقي
• object: نار المخيم
• time expression: خلال الليل

Arabic can also use a subject-first order in some contexts, but verb-first is very common.

Yes. يشعل already includes the meaning he lights because the verb is marked for 3rd person masculine singular.

So:

• يشعل = he lights / he is lighting
• صديقي tells you who that he is: my friend

Arabic often works this way: the verb already contains person information, and then a noun can be added to identify the subject more clearly.

يشعل is in the imperfect form. In Modern Standard Arabic, the imperfect can express several related meanings depending on context, such as:

• he lights
• he is lighting
• he lights regularly
• sometimes even he will light

In this sentence, with no extra context, it most naturally sounds like a present or habitual action: my friend lights the campfire during the night.

يشعل comes from the verb أشعل, which means to ignite, to set on fire, or to light.

This is a Form IV verb. Its pattern is:

• past: أشعل
• imperfect: يشعل in plain spelling, more fully يُشْعِلُ

So يشعل is a transitive verb here: it takes an object, namely نار المخيم.

The -ي at the end means my.

So:

• صديق = friend
• صديقي = my friend

This -ي is an attached possessive pronoun. Arabic often shows possession by attaching pronouns directly to nouns.

Because نار المخيم is an iḍāfa construction, often called the genitive construction or annexation.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun determines whether the whole phrase is definite

So:

• نار المخيم = the fire of the camp / the campfire

Since المخيم is definite, the whole phrase is definite, even though نار itself does not have الـ.

Yes, literally it is something like:

• نار = fire
• المخيم = the camp

So نار المخيم literally means the fire of the camp or the camp’s fire.

In natural English, that is often best translated as the campfire.

This is a very common feature of Arabic: instead of using an apostrophe like English, Arabic often links two nouns together in an iḍāfa.

خلال الليل means during the night or throughout the night.

It suggests time within the span of the night.

By contrast:

• في الليل = at night / in the night
• خلال الليل = during the night

So خلال is a little more specific about something happening within that period of time.

Also notice that الليل has الـ. In Arabic, time expressions often use the definite article where English may not translate it literally.

A fully vocalized version is:

يُشْعِلُ صَديقِي نارَ المُخَيَّمِ خِلالَ اللَّيْلِ

A careful pronunciation would be approximately:

yushʿilu ṣadīqī nāra al-mukhayyami khilāla al-layli

Useful notes:

• يُشْعِلُ = yushʿilu
• صديقي = ṣadīqī
• نارَ shows the object in the accusative
• المخيمِ is genitive because it is the second part of the iḍāfa
• خلالَ is an adverbial accusative form here
• اللَّيلِ is genitive after خلال

If the sentence is fully vowelled, the grammar looks like this:

• يُشْعِلُ = verb
• صديقي = subject, so it is nominative
• نارَ = direct object, so it is accusative
• المخيمِ = genitive, because it is the second noun in the iḍāfa
• خلالَ = accusative in this adverbial use
• اللَّيلِ = genitive after خلال

In normal everyday Arabic writing, these short vowels are usually omitted, so learners often read the sentence without seeing the endings.

At an early stage, the most important thing is usually to understand:

• who is doing the action
• what the action is
• what the object is
• how the nouns connect in the iḍāfa

The full case system matters most in careful reading, formal writing, and advanced grammar study.