زوجتي في البيت.

Because Arabic often omits the present-tense verb “to be”.

So زوجتي في البيت is literally something like:

• زوجتي = my wife
• في البيت = in the house / at home

In English, we need is: My wife is at home.
In Arabic, in a simple present-tense sentence like this, is is usually understood and not said.

If you wanted a past tense, then Arabic would use a verb, for example:

• كانت زوجتي في البيت = My wife was at home

A good pronunciation guide is:

zawjatī fī l-bayt

A slightly more detailed version is:

• زوجتي = zaw-ja-tī
• في = fī
• البيت = al-bayt or, in connected speech after في, often l-bayt

A few notes:

• ز sounds like z
• وْ here helps form the zaw sound
• ج in Modern Standard Arabic is usually taught as j as in judge
• تي at the end of زوجتي sounds like tī
• بيت rhymes roughly with bait in English

زوجتي breaks down into:

• زوجة = wife
• -ي = my

So the whole word means my wife.

This is very common in Arabic: instead of using a separate word for my, Arabic often attaches a suffix directly to the noun.

Examples:

• كتابي = my book
• بيتي = my house
• زوجتي = my wife

Because the final ة (taa marbuuTa) changes pronunciation when a suffix is attached.

By itself:

• زوجة = zawja(h) = wife

But when you add -ي (my), the ة is no longer pronounced like a final -a / -ah sound. It becomes a clear t sound:

• زوجتي = zawjatī

This happens very often:

• سيارة = car

• سيارتي = my car

• مدرسة = school
• مدرستي = my school

So in this sentence, hearing the t in زوجتي is completely normal and important.

في means in.

It is a preposition, and it introduces the place where something is.

So:

• في البيت = in the house / at home

A useful grammar point: after في, the following noun is in the genitive case in formal grammar.

So in fully vowelled Arabic, you would see:

• في البيتِ

That final -i sound on البيتِ is the genitive ending.

Because الـ means the.

So:

• بيت = a house / house
• البيت = the house

In this sentence, البيت often has the natural English meaning home, so the whole sentence is commonly understood as My wife is at home.

Arabic often uses the house where English prefers home.

So depending on context:

• في البيت = in the house
• في البيت = at home

Both are possible.

Yes. In البيت, the ل of الـ is pronounced.

That is because ب is a moon letter, not a sun letter.

So:

• البيت = al-bayt / l-bayt in connected speech

Compare that with a sun-letter word such as الشمس:

• الشمس is pronounced ash-shams, not al-shams

So here, with البيت, keep the l sound.

In fully vowelled formal Arabic, it would be:

زَوْجَتِي فِي الْبَيْتِ

The important visible ending here is on البيتِ, because في makes it genitive.

For زوجتي, the situation is a little more advanced:

• it is the subject of a nominal sentence
• so it is nominative in function
• but because it has the -ي suffix (my), the case ending is not shown in the usual simple way

So for a learner, the main practical point is:

• زوجتي = subject
• في البيتِ = prepositional phrase telling location

Yes, but the emphasis may change.

The neutral order is:

• زوجتي في البيت = My wife is at home

You could also say:

• في البيت زوجتي

This is more marked and can sound like As for being in the house, it is my wife, or it may emphasize the location.

For learners, the first version is the best default pattern to use.

Yes, زوجتي في البيت is perfectly good Modern Standard Arabic.

In everyday speech, dialects may say similar things, but pronunciation and wording can change. For example, some dialects might prefer a different word for wife, or might use a shorter everyday expression for at home.

But as MSA, this sentence is clear, natural, and grammatically solid.

So if you are learning Modern Standard Arabic, this is a good sentence model:

• [noun + possessive] + [prepositional phrase]
• زوجتي في البيت
• أخي في المدرسة
• كتابي على الطاولة