ما دیروز در اداره داشتیم درباره پروژه صحبت میکردیم که مدیر وارد اتاق شد.

This is a very common learner question.

Both forms can refer to an ongoing action in the past, but داشتیم + imperfect verb makes the progressive idea more explicit.

• صحبت می‌کردیم = we were talking / we used to talk / we talked depending on context
• داشتیم صحبت می‌کردیم = we were in the middle of talking

So here, داشتیم helps emphasize that the action was already in progress when something else happened.

In this sentence:

• داشتیم ... صحبت می‌کردیم shows an ongoing background action
• مدیر وارد اتاق شد shows the interrupting event

This is very similar to English We were talking ... when the manager came in.

Here که connects the ongoing action to the event that interrupts it.

In this sentence, که is functioning like:

• when
• and then
• at which point

So:

• داشتیم درباره پروژه صحبت می‌کردیم که... = we were talking about the project when...

This use of که is extremely common in Persian narrative style. It does not always mean a literal that. Its meaning depends heavily on context.

Persian word order is usually Subject + Time + Place + Other information + Verb.

So in your sentence:

• ما = subject
• دیروز = time
• در اداره = place
• داشتیم درباره پروژه صحبت می‌کردیم = main action
• که مدیر وارد اتاق شد = following event

A more word-for-word structure would look like:

• We yesterday at the office were talking about the project when the manager entered the room.

That sounds odd in English, but it is normal in Persian.

Also remember that Persian is generally verb-final, so the main verb tends to come near the end of its clause.

Usually, yes, it could be omitted.

Persian often drops subject pronouns because the verb ending already shows the subject.

• داشتیم = we were having / we were
• می‌کردیم = we were doing

These endings already show we, so ما is often optional.

So both are natural:

• ما دیروز در اداره داشتیم درباره پروژه صحبت می‌کردیم...
• دیروز در اداره داشتیم درباره پروژه صحبت می‌کردیم...

Including ما may add:

• emphasis
• contrast
• clarity

For example, if you want to stress we as opposed to someone else, keeping ما makes sense.

Persian has no definite article like English the.

So:

• پروژه can mean project or the project
• اداره can mean office or the office
• اتاق can mean room or the room

The context tells you which meaning is intended.

If you want to make something more specific in Persian, you usually rely on:

• context
• word order
• demonstratives like این (this) or آن (that)
• sometimes other grammatical cues

So Persian learners coming from English often expect a separate word for the, but there isn’t one.

Because پروژه is not the direct object of the verb here.

In the sentence, we have:

• درباره پروژه = about the project

Since پروژه comes after the preposition درباره (about), it is part of a prepositional phrase, not a direct object.

را is used for specific direct objects, not for nouns after prepositions.

Compare:

• درباره پروژه صحبت می‌کردیم = we were talking about the project
• پروژه را شروع کردیم = we started the project

In the second example, پروژه is the direct object, so را appears.

Yes. درباره ... صحبت کردن is a very common way to say to talk about ....

Here:

• درباره = about / concerning
• صحبت کردن = to talk / to speak

So:

• درباره پروژه صحبت کردن = to talk about the project

There are several natural alternatives in Persian, such as:

• راجع به پروژه صحبت می‌کردیم
• در مورد پروژه صحبت می‌کردیم

All of these are common, though their tone may differ slightly:

• درباره is a bit more formal or neutral
• راجع به is very common in speech
• در مورد is also very common and neutral

This is because Persian often uses compound predicates.

Here:

• وارد = entering / entered / inside as an adjective or participle-like element
• شد = became

Together, وارد شد means entered.

So:

• مدیر وارد اتاق شد = the manager entered the room

This is a very normal Persian pattern. Many verbs are built from:

• a non-verbal element
• plus a light verb such as کردن or شدن

Other examples:

• خارج شد = went out / exited
• شروع کرد = started
• تمام شد = finished / ended

So you should learn وارد شدن as a complete verb meaning to enter.

Because with وارد شدن, Persian often allows the destination noun directly after وارد, without a preposition.

So this is normal:

• وارد اتاق شد = he entered the room

You may also encounter:

• به اتاق وارد شد

but the version without به is very common and natural.

This is one of those things where English learners may expect a preposition because English uses enter the room but go into the room. Persian simply has its own pattern, and وارد اتاق شدن is a standard one.

It is the imperfect form of the compound verb صحبت کردن.

The structure is:

• می‌ = imperfect/habitual/progressive marker
• کردیم = we did

Since صحبت کردن literally uses کردن as its light verb, the conjugated part is کردیم.

So:

• صحبت می‌کردیم literally looks like we were doing talk
• but it simply means we were talking

In context, this imperfect form often means:

• ongoing past action
• habitual past action
• background action in a narrative

Here, because of the surrounding context and especially because of داشتیم, it clearly means an ongoing past action: we were talking.

This is about spelling conventions.

The standard modern spelling is:

• می‌کردیم

with a half-space after می.

But many people write informally as:

• میکردیم

especially in casual typing.

So:

• می‌کردیم = standard
• میکردیم = common informal typing

They mean the same thing.

You may also notice the same with other verbs:

• می‌روم / میروم
• می‌گفت / میگفت

If you are learning Persian formally, it is best to get used to the standard form with the half-space.

Yes. Persian word order is flexible, especially with time and place expressions.

Your sentence puts them in a very natural order:

• ما دیروز در اداره ...

But other orders are also possible, depending on emphasis:

• ما در اداره دیروز داشتیم درباره پروژه صحبت می‌کردیم...
• دیروز ما در اداره داشتیم درباره پروژه صحبت می‌کردیم...
• در اداره دیروز داشتیم درباره پروژه صحبت می‌کردیم...

Not all options sound equally neutral, but they are grammatical.

In general:

• time and place phrases are fairly movable
• the verb usually stays near the end
• moving things around changes emphasis more than basic meaning

The version you have is straightforward and natural.

Yes, در اداره is perfectly correct, but in casual speech people often use تو instead of در for in.

So you may hear:

• در اداره = more formal or written-sounding
• تو اداره = very common in speech

Both mean in the office / at the office.

This difference is similar to the difference between more formal and more conversational choices in many languages. If you are reading written Persian, در appears a lot. If you are listening to everyday conversation, تو is extremely common.

A spoken version might be something like:

• ما دیروز تو اداره داشتیم راجع به پروژه صحبت می‌کردیم که مدیر وارد اتاق شد.

Possible spoken-style changes:

• در → تو
• درباره → راجع به

Also, in actual speech, the pronoun ما might be dropped:

• دیروز تو اداره داشتیم راجع به پروژه صحبت می‌کردیم که مدیر وارد اتاق شد.

And in very natural conversation, pronunciation may reduce a bit, but the grammar stays basically the same.

So the original sentence is correct and natural, but it leans a little more toward careful or standard Persian than casual speech.