اختي هتقعد في البيت النهارده عشان عندها برد.

In informal Egyptian Arabic writing, hamzas are often omitted, so اختي is the same word as أختي.

Also, the ending -ي is the possessive suffix meaning my:

• أخت = sister
• أختي / اختي = my sister

So the first word is simply my sister.

Because Arabic verbs already show person and gender.

In هتقعد, the verb itself tells you who the subject is. In this sentence, اختي makes it clear that the subject is feminine singular, so you do not need to add هي.

You could say هي هتقعد for extra emphasis, but it is not necessary in a normal sentence.

هتقعد can be broken down like this:

• هـ = future marker, meaning will / going to
• تـ = present-tense prefix
• قعد = the verb root related to sitting/staying

So هتقعد means she will sit / she will stay.

A useful thing to know: تـ can also mark you masculine singular in other contexts, so context matters. Here, because the subject is اختي, it means she.

Here it means stay.

The verb قعد often literally means sit, but in Egyptian Arabic it is also commonly used for stay, remain, or spend time somewhere.

So:

• هتقعد في البيت = she will stay at home / stay in the house

It does not necessarily mean she will literally be sitting down.

In Cairene Egyptian, ق is usually pronounced as a glottal stop, like the break in the middle of uh-oh.

So هتقعد is not pronounced with a strong q sound like in Modern Standard Arabic. It sounds more like ha-ti-ʔaʿod or ha-te-ʔod depending on how narrowly you represent the pronunciation.

The important point for a learner is:

• ق in Egyptian often sounds like ء

It can mean either, depending on context.

Literally:

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

In this sentence, في البيت is very naturally understood as at home.

In speech, في البيت is often pronounced together as fil-bēt.

النهارده means today in Egyptian Arabic.

You may also see:

• النهاردة

Both are common spellings for the same word in colloquial writing.

This is one of those everyday Egyptian words that differs from Modern Standard Arabic, where you would usually learn اليوم for today.

Here عشان means because.

So:

• عشان عندها برد = because she has a cold

But عشان is a very flexible Egyptian word. Depending on context, it can also mean:

• so that
• for
• because of

You may also see علشان, which is just a fuller form and means the same thing.

This is a very common Arabic pattern.

• عند literally means something like at or with
• عندها literally means at her
• but idiomatically it means she has

So:

• عندها برد = she has a cold

A few important notes:

1. Arabic often does not use an indefinite article like a, so برد by itself can mean a cold.
2. برد literally relates to cold, but here it means the illness, not just low temperature.
3. If you wanted to say she feels cold, Egyptian would often use something like بردانة for a woman instead.

Yes, to some extent.

The given sentence is very natural:

• اختي هتقعد في البيت النهارده عشان عندها برد

But Egyptian Arabic allows some flexibility. For example:

• النهارده اختي هتقعد في البيت عشان عندها برد
• عشان عندها برد، اختي هتقعد في البيت النهارده

The meaning stays basically the same, but the emphasis changes:

• putting النهارده earlier emphasizes today
• putting عشان عندها برد earlier emphasizes the reason

So the original order is natural, but it is not the only possible one.