يقف صديقي عند الباب.

A careful pronunciation is:

yaqifu ṣadīqī ʿinda al-bābi

In normal pause, many speakers will not pronounce the final short case vowels, so you may also hear something closer to:

yaqif ṣadīqī ʿind al-bāb

Word by word:

• يقف = yaqifu
• صديقي = ṣadīqī
• عند = ʿinda
• الباب = al-bābi

يقف is a present-tense verb, third person singular masculine.

So it means:

• he stands
• he is standing

In Arabic, the present tense often covers both simple present and present progressive, and context tells you which is more natural.

Because Arabic verbs already include the subject information.

In يقف, the form itself tells you the subject is:

• third person
• singular
• masculine

So يقف already means he stands / he is standing. You do not need هو unless you want emphasis.

For example:

• يقف صديقي عند الباب = My friend is standing at the door
• هو يقف عند الباب = He is standing at the door (with an explicit pronoun)

Because this is a very common Arabic sentence pattern: verb + subject + rest of sentence.

So:

• يقف = the verb
• صديقي = the subject
• عند الباب = the prepositional phrase

This is called a verbal sentence.

Arabic can also use:

• صديقي يقف عند الباب

That is also grammatical. It feels more like My friend, he is standing at the door or puts more focus on my friend.

صديقي means my friend.

It is made from:

• صديق = friend
• ـي = my

So literally it is friend-my, which is how possession is commonly expressed in Arabic.

The ending ـي is the attached pronoun for my.

Other similar examples:

• كتابي = my book
• بيتي = my house
• أخي = my brother

When a noun is attached to ـي meaning my, the form changes in a way that hides the usual visible case ending.

So even though صديقي is the subject of the sentence, you do not see an extra ending written after it.

Also, in normal Arabic writing, short vowels are usually not written anyway. So learners often have to understand the grammatical role from word order and syntax, not from visible endings alone.

عند usually means at, by, near, or in the presence of, depending on context.

In this sentence, عند الباب means at the door or by the door.

It is very common for location:

• عند البيت = at the house
• عند المدرسة = at the school

It is not exactly the same as في:

• في البيت = in the house
• عند البيت = at/by the house

Because عند is a preposition, and the noun after a preposition comes after it.

So:

• عند = at/by
• الباب = the door

Together:

• عند الباب = at the door

Grammatically, the noun after a preposition is in the genitive case. So in fully vocalized Arabic it would be عند البابِ.

Because الباب means the door, while باب means a door or just door.

So:

• عند الباب = at the door
• عند باب = at a door

Arabic does not have a separate word for a/an. Indefiniteness is usually shown simply by leaving off الـ.

Because ب is a moon letter.

In Arabic, the l of الـ is:

• pronounced with moon letters
• assimilated with sun letters

Since ب is a moon letter, you say:

• al-bāb

Compare that with a sun-letter word such as:

• الشمس pronounced ash-shams

So الباب keeps the l sound.

This verb comes from the root و ق ف, seen clearly in the past tense:

• وقف = waqafa = he stood

But in the present tense, verbs of this type often drop the initial و. So:

• وقف → يقف
• waqafa → yaqifu

This is a normal pattern for many verbs with an initial weak letter و. So although the root contains و, the present-tense form does not show it here.

Sometimes, yes, but they are not exactly the same form.

• يقف = a finite verb = he stands / he is standing
• واقف = an active participle = standing

In many real-life contexts, especially outside very formal grammar explanations, واقف عند الباب can also mean standing at the door.

But in this sentence, يقف صديقي عند الباب is the straightforward verbal sentence and a very good standard example for learners.