البحيرة كبيرة.

In Arabic, the verb to be is usually not said in the present tense.

So البحيرة كبيرة literally looks like:

• the lake
• big

But it means The lake is big.

This is very normal in both Standard Arabic and Egyptian Arabic. If you want other tenses, then Arabic does use a verb, such as كان for was.

• البحيرة كبيرة = The lake is big
• البحيرة كانت كبيرة = The lake was big

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

So:

• بحيرة كبيرة = a big lake
• literally: lake big

This is the normal word order in Arabic. English does it the other way around:

• English: big lake
• Arabic: lake big

In your sentence, though, كبيرة is not just an adjective inside a noun phrase. It is the predicate of the sentence:

• البحيرة = the topic / subject
• كبيرة = the description being said about it

So the full sentence means The lake is big.

This is a very important point.

In البحيرة كبيرة, كبيرة is acting as the predicate adjective, not as part of a phrase like the big lake.

So:

• البحيرة كبيرة = The lake is big
• البحيرة الكبيرة = the big lake

That difference matters a lot.

Compare:

• البحيرة كبيرة
  = The lake is big

• البحيرة الكبيرة
  = the big lake

So if an English speaker expects both words to have الـ, that is only true when the adjective is directly modifying the noun inside a noun phrase, not when it is the predicate of a sentence.

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

Arabic adjectives agree with the noun in things like:

• gender
• number
• definiteness

Since بحيرة is feminine, the adjective is feminine too:

• masculine: كبير = big
• feminine: كبيرة = big

So:

• البحر كبير = The sea is big
• البحيرة كبيرة = The lake is big

The ending ـة is a very common feminine marker.

No. In Arabic, grammatical gender is not the same as biological sex.

A lake is not female in real life, of course, but the word بحيرة is grammatically feminine. One clue is that it ends in ـة, which often marks feminine nouns.

So learners should think:

• feminine noun = a grammar category
• not necessarily something actually female

Because بحيرة is grammatically feminine, the adjective must also be feminine:

• بحيرة كبيرة

A common Egyptian pronunciation would be roughly:

• el-boḥeira kebīra or
• il-boḥeira kebīra

A few notes:

• الـ is usually pronounced el- or il- in Egyptian
• بحيرة is often pronounced something like boḥeira
• كبيرة is often pronounced kebīra

A rough English-friendly approximation is:

• el-bo-HE-ra ke-BEE-ra

The ḥ sound in boḥeira is a strong h sound from deep in the throat.

The letter ح is not the same as the normal English h.

It is a stronger, breathier throat sound. It is voiceless and produced deeper in the throat than English h.

So in بحيرة, try not to say a plain English buh-heera. Instead, aim for something more like:

• boḥeira

If you cannot produce it perfectly yet, that is very common for beginners. A plain h is often understood, but it is good to notice the difference early.

Because the next letter is ب, and ب is a moon letter.

In Arabic, the definite article الـ is pronounced in two different ways:

• with a clear l before moon letters
• with assimilation before sun letters

Since ب is a moon letter, you say the l:

• البحيرة = el-buḥeira / il-buḥeira

If the next letter were a sun letter, the l would disappear in pronunciation.

The written form البحيرة كبيرة works perfectly well in Standard Arabic, and it is also natural in Egyptian Arabic writing.

The main difference is usually in pronunciation, not in the basic structure.

Standard Arabic pronunciation:

• al-buḥayratu kabīratun in full formal pronunciation
• more commonly without case endings: al-buḥayra kabīra

Egyptian pronunciation:

• el-boḥeira kebīra

So an Egyptian learner can absolutely use this sentence, but should pronounce it in the Egyptian way if speaking dialect.

That would be:

• البحيرة الكبيرة

This is different from:

• البحيرة كبيرة

The difference:

• البحيرة الكبيرة = the big lake
• البحيرة كبيرة = The lake is big

This is one of the most useful contrasts for learners to master.

Why?

Because in Arabic:

• an adjective inside a noun phrase matches the noun in definiteness
• but a predicate adjective in a sentence is usually indefinite

So:

• البحيرة الكبيرة = noun + definite adjective
• البحيرة كبيرة = subject + predicate adjective

Yes, but it means something different.

• بحيرة كبيرة = a big lake
• البحيرة كبيرة = The lake is big

So adding or removing الـ changes the meaning:

• بحيرة = a lake
• البحيرة = the lake

This is very important in Arabic, since definiteness is shown directly on the noun.

The basic forms are:

• بحيرة = lake
• كبير = big

In the sentence, كبير becomes كبيرة because it has to agree with the feminine noun بحيرة.

So you can think of it like this:

• dictionary adjective: كبير
• feminine form: كبيرة

In a simple sentence like this, البحيرة كبيرة is the normal and most natural order.

Arabic can sometimes change word order for emphasis, but as a learner, the best pattern to remember is:

• noun + adjective/predicate

So for now, treat this as the standard pattern:

• البحيرة كبيرة
• المدينة جميلة
• البيت واسع

This will help you build many simple present-tense descriptions in Egyptian Arabic.