اختي جاهزة للسفر بكرة.

A natural Egyptian pronunciation is:

okhti gāhza les-safar bokra

A rough word-by-word guide:

• اختي / أختي → okhti
• جاهزة → gāhza
• للسفر → les-safar
• بكرة → bokra

Two useful notes:

• In Egyptian Arabic, ج is usually pronounced g, not j.
• In للسفر, you hear a doubled s sound.

Because Arabic usually does not use a present-tense verb "to be" in sentences like this.

So instead of saying something literally like My sister is ready, Arabic simply says:

• اختي جاهزة
• literally: my sister ready

This is completely normal.

If you wanted past or future, then Arabic would use other forms, for example:

• كانت جاهزة = she was ready
• هتبقى جاهزة = she will be ready

The ending -ي means my.

So:

• أخت / اخت = sister
• أختي / اختي = my sister

This is a very common Arabic pattern: possession is often shown by adding a suffix directly to the noun.

For example:

• أختك = your sister
• أخته = his sister
• أختها = her sister

Because اختي refers to a female, and Arabic adjectives must agree with the noun they describe.

So:

• جاهز = masculine ready
• جاهزة = feminine ready

Since sister is feminine, the adjective must also be feminine:

• اختي جاهزة

If the sentence were about a brother, you would say:

• أخويا جاهز

Here, لـ gives the sense of for or to, and with جاهز/جاهزة it often means ready for or ready to.

So:

• جاهزة للسفر
• literally something like ready for travel
• naturally in English: ready to travel

This is a very common structure in Arabic:

• جاهز للشغل = ready for work
• جاهزة للامتحان = ready for the exam

This is one of those places where Arabic and English do not match word-for-word.

السفر here is a verbal noun, meaning travel/traveling, and Arabic often uses الـ with abstract nouns or verbal nouns in places where English would not use the.

So even though للسفر literally looks like for the travel, you should understand it as the natural Arabic way to say:

• to travel
• for travel
• for traveling

In other words, translate the whole phrase naturally, not piece by piece.

Because two things are happening:

1. لـ

   • الـ combine in writing
   • ل + السفر becomes للسفر

2. س is a sun letter, so the l sound of الـ disappears in pronunciation and the next consonant gets doubled

So although it is written للسفر, it is pronounced approximately:

• les-safar or lis-safar

with a doubled s sound.

This is the same kind of thing you hear in many Arabic words with the definite article before sun letters.

Yes, بكرة is a very common everyday word in Egyptian Arabic meaning tomorrow.

It is also used in some other dialects, but it is especially familiar to learners as an Egyptian word.

In Modern Standard Arabic, you would more likely see:

• غدًا

So this sentence feels more colloquial and natural for spoken Egyptian than for formal written Arabic.

In careful standard spelling, you would usually write:

• أختي

But in informal typing, many people drop the hamza and write:

• اختي

So for a learner:

• أختي = more careful / standard spelling
• اختي = very common informal spelling

Both are easily understood.

Yes.

A few natural alternatives are:

• أختي مستعدة للسفر بكرة
  This is a bit more formal or more like prepared/ready.

• بكرة أختي جاهزة للسفر
  This puts more emphasis on tomorrow.

• أختي جاهزة تسافر بكرة
  In speech, some speakers may use a structure like this, though جاهزة للسفر is very solid and natural.

So the original sentence is good, natural Egyptian Arabic, especially in everyday use.