قبل الغداء أضع الدجاج في الفرن.

Arabic often allows more flexible word order than English. Starting with قبل الغداء puts the time expression first for emphasis or context, like Before lunch, I put...

You could also say:

أضع الدجاج في الفرن قبل الغداء

That version is also correct. The original sentence simply foregrounds the time.

قبل means before, and here it functions as a time expression.

It is followed by a noun in the genitive, so:

• قبل = before
• الغداء = lunch

Together: قبل الغداء = before lunch

In fully marked Arabic, this would be:

قَبْلَ الغَدَاءِ

So الغداء is genitive because it comes after قبل.

الـ is the definite article, meaning the.

So:

• غداء = lunch / a lunch
• الغداء = the lunch

In many everyday contexts, the lunch is best understood in English simply as lunch, especially when talking about a meal in general.

أضع is the 1st person singular imperfect form of the verb وضع (to put / to place).

So أضع means:

• I put
• I am putting
• sometimes I will put, depending on context

In this sentence, it most naturally means I put or I am putting.

In the imperfect tense, Arabic verbs take prefixes that show the subject.

For وضع:

• أضع = I put
• تضع = you put / she puts
• يضع = he puts
• نضع = we put

So the initial أ marks I.

Because Arabic verbs already contain subject information.

أضع already means I put, so the pronoun أنا is not necessary.

You could say:

أنا أضع الدجاج في الفرن

But that usually adds emphasis, like I put the chicken in the oven.

الدجاج means the chicken.

Arabic often uses the definite article where English may or may not use it, depending on context. Here it likely refers to a specific chicken or chicken dish already understood in the situation.

So:

• دجاج = chicken
• الدجاج = the chicken

Also, الدجاج can refer to chicken as food, not only a live animal.

Because it is the direct object of أضع.

The action is put, and the thing being put is the chicken, so:

• أضع = I put
• الدجاج = the chicken

In fully vocalized MSA, it would be:

أضعُ الدجاجَ

The ending -a on الدجاجَ marks it as the direct object (accusative case).

في means in.

So:

• في = in
• الفرن = the oven

Together: في الفرن = in the oven

Arabic uses في here just as English uses in with oven.

Because it comes after the preposition في.

Prepositions in Arabic make the following noun genitive, so in full case marking:

في الفرنِ

That final -i sound is the genitive ending.

Yes. The imperfect tense in Arabic can express several ideas depending on context, including:

• a present action: I am putting
• a repeated action / habit: I put
• sometimes near future: I will put

So this sentence could mean:

• Before lunch, I put the chicken in the oven
  or
• Before lunch, I usually put the chicken in the oven

Context tells you which is intended.

A fully vocalized MSA version would be:

قَبْلَ الغَدَاءِ أَضَعُ الدَّجَاجَ فِي الفُرْنِ

This shows the grammatical endings clearly:

• قَبْلَ = accusative adverbial form
• الغَدَاءِ = genitive after قبل
• أَضَعُ = imperfect verb, 1st person singular
• الدَّجَاجَ = accusative direct object
• فِي الفُرْنِ = genitive after في

A reasonable pronunciation is:

qabla al-ghadā’i aḍaʿu ad-dajāja fī al-furni

A few useful notes:

• غ = a French-style r / a throaty gh
• ض = an emphatic d
• ع = a deep throat sound with no exact English equivalent
• ج in MSA is usually pronounced like j in judge

Also, in careful pronunciation, the l of ال is pronounced here, because غ, د, and ف are not sun letters.

Yes, but the meaning shifts slightly.

• في الفرن = in the oven
• داخل الفرن = inside the oven

في الفرن is the most normal, neutral choice here. داخل الفرن adds a bit more emphasis to the idea of being physically inside.

A useful root here is و-ض-ع from وضع (to put / place).

From that root you get forms like:

• وضع = he put
• يضع = he puts
• أضع = I put
• موضع = place/location
• وضع can also mean situation or condition in some contexts

Recognizing roots helps you connect related words more easily as you learn Arabic.