المكتب في الناحية التانية.

A natural pronunciation is:

el-maktab fin-naḥya t-tānya

You may also see it written as:

il-maktab fin-naḥya t-tānya

A few notes:

• المكتب = el-maktab
• في الناحية often runs together in speech as fin-naḥya
• التانية is pronounced et-tānya, but after naḥya you’ll often hear the t attached smoothly: naḥya t-tānya
• The ḥ in ناحية is the Arabic ح, a stronger, breathier sound than English h

Because Arabic normally leaves out is/are in the present tense.

So the structure is basically:

المكتب = the office / the desk
في الناحية التانية = on the other side / in the other direction

Literally, it is something like:

The office in the other side.

That is completely normal in Arabic. If you want to talk about the past or future, then forms of to be are expressed differently.

مكتب can mean both office and desk, depending on context.

So:

• المكتب can be the office
• or the desk

In everyday speech, context usually makes it clear. If the meaning shown to you was office, that is perfectly natural. But a learner should know the word itself can also refer to a desk.

ناحية means side, direction, or sometimes area/part.

In this sentence, في الناحية التانية means something like:

• on the other side
• in the other direction
• in the other part/area

So ناحية is a flexible location word, not just a strict geometric side.

Because this is Egyptian Arabic, not formal Standard Arabic.

In Standard Arabic, you would more often see:

• الثانية
• or sometimes another word such as الأخرى, depending on the exact meaning

In Egyptian Arabic:

• ث is very often pronounced as ت
• so الثانية becomes التانية in normal speech and very often in informal writing too

Also, in Egyptian تاني / تانية is very common for meanings like:

• second
• another
• other

So الناحية التانية is a very normal Egyptian way to say the other side.

Because in Arabic, adjectives usually come after the noun they describe.

So:

• الناحية التانية = literally the side the-other

This is the normal Arabic order:

• noun first
• adjective second

That is why you do not say التانية الناحية here.

Because Arabic adjectives agree with the nouns they describe in definiteness.

So if the noun is definite:

• الناحية = the side

then the adjective must also be definite:

• التانية = the other / the second

Together:

• الناحية التانية = the other side

If the noun were indefinite, the adjective would also be indefinite.

Because ناحية is a feminine noun, and the adjective has to agree with it.

So:

• ناحية is feminine
• therefore the adjective is feminine too: تانية

Compare:

• مكان تاني = another place
• ناحية تانية = another side

So تاني is masculine, while تانية is feminine.

This is because of sun letters.

The Arabic definite article ال is not always pronounced the same way. When the next letter is a sun letter, the l sound assimilates to that letter.

Here:

• الناحية starts with ن, a sun letter
  so it is pronounced en-naḥya
• التانية starts with ت, also a sun letter
  so it is pronounced et-tānya

That is why you do not pronounce a clear l in those two words.

Yes. في is often taught first as in, but in real Arabic it covers a wider range of location meanings, depending on context.

It can often correspond to:

• in
• at
• sometimes something close to on or over in

In في الناحية التانية, the idea is location:

• in/on the other side
• over on the other side
• in the other direction

So you should not expect a one-for-one match with English prepositions every time.

Yes. A few alternatives are:

• المكتب في الجهة التانية = the office is on the other side
• المكتب هناك = the office is over there
• المكتب في الناحية دي؟ لا، في الناحية التانية = Is the office on this side? No, it’s on the other side.

Each version has a slightly different feel:

• ناحية = side/direction
• جهة = side/direction, often a bit neater or more neutral
• هناك = there/over there, less specific

It is a very common Arabic pattern:

[noun] + [prepositional phrase]

Here:

• المكتب = the office
• في الناحية التانية = on the other side

So the whole sentence is a simple location sentence:

• The office is on the other side.

This pattern is extremely common in Egyptian Arabic:

• الحمام هنا = the bathroom is here
• الشنطة على الكرسي = the bag is on the chair
• المفتاح في العربية = the key is in the car

So this sentence is a good model for many everyday location sentences.