V půl osmé je moje sestra skoro vždycky už v kuchyni.

This is one of the classic Czech time expressions that feels strange to English speakers at first.

V půl osmé literally means at half of the eighth hour, so it refers to the halfway point before eight o’clock, which is 7:30.

Czech often counts toward the next hour in this pattern:

• v půl osmé = 7:30
• v půl deváté = 8:30
• v půl druhé = 1:30

So the number tells you the coming hour, not the one that has already started.

Because after půl, Czech uses the genitive form of the following hour.

So:

• půl osmé = half of the eighth

The form osmé is the feminine genitive singular form of osmý. It agrees with an understood feminine noun, traditionally hodina.

So the full underlying idea is something like:

• v půl osmé hodiny

In normal Czech, hodiny is simply left out.

Here v means at in a time expression.

Czech often uses v with clock times:

• v pět = at five
• v osm hodin = at eight o’clock
• v půl osmé = at half past seven

So v is not literally in here in the English sense. In this context, it is just the normal preposition used for a point in time.

Už means already.

It tells you that by 7:30, your sister has already reached the kitchen. Without už, the sentence would still make sense, but it would lose that nuance of by then / already at that time.

Compare:

• V půl osmé je moje sestra skoro vždycky v kuchyni.
  = At 7:30 my sister is almost always in the kitchen.

• V půl osmé je moje sestra skoro vždycky už v kuchyni.
  = At 7:30 my sister is almost always already in the kitchen.

So už emphasizes that this has happened by that point.

They do different jobs.

• skoro vždycky = almost always
• už = already

So the sentence combines:

• frequency: this happens on most occasions
• timing: by that time, it has already happened

The overall idea is:

• By 7:30, my sister is already in the kitchen almost every time.

So there is no real overlap. One tells you how often, the other tells you how early.

Kuchyni is the locative singular of kuchyně.

After v when it means in or inside a place, Czech normally uses the locative:

• v kuchyni = in the kitchen
• v domě = in the house
• v práci = at work

Here the sentence describes location, not motion. Your sister is located in the kitchen.

If you wanted to express movement into the kitchen, Czech would normally use:

• do kuchyně = into the kitchen

So:

• je v kuchyni = she is in the kitchen
• jde do kuchyně = she is going into the kitchen

Because the subject is moje sestra, which is singular.

• moje sestra je = my sister is

In the present tense, být agrees with the subject in person and number:

• já jsem
• ty jsi
• on/ona je
• my jsme
• vy jste
• oni jsou

So je is used because sestra is third-person singular.

Not in the present tense.

Even though sestra is feminine, the form je is the same for:

• bratr je = brother is
• sestra je = sister is
• dítě je = child is

So in the present tense, být does not show gender. Gender shows up more clearly in the past tense, for example:

• byl = he was
• byla = she was
• bylo = it was

Yes. Czech word order is flexible, and changes in order usually change emphasis, not basic meaning.

The given sentence is natural:

• V půl osmé je moje sestra skoro vždycky už v kuchyni.

But you could also hear:

• Moje sestra je v půl osmé skoro vždycky už v kuchyni.
• V půl osmé už je moje sestra skoro vždycky v kuchyni.

These all mean roughly the same thing, but they highlight different parts:

• starting with V půl osmé emphasizes the time
• moving už earlier can make the already idea more prominent
• starting with Moje sestra emphasizes the person

So the original order is not the only possible one, just a natural one.

Yes, both mean my sister.

• moje sestra
• má sestra

In everyday speech, moje is often very common and sounds completely natural. Má is also correct, but can sound a little shorter, sometimes slightly more formal or stylistically different depending on context.

So in this sentence, either could work:

• V půl osmé je moje sestra...
• V půl osmé je má sestra...

For many learners, moje feels easier and more transparent at first.

Yes. You could say:

• V sedm třicet... = At 7:30...
• V sedm hodin třicet minut... = At seven hours thirty minutes...

But v půl osmé is the more natural everyday Czech way to say 7:30.

So although the digital-style version exists, Czech speakers very often prefer the half-hour expression in normal conversation.

Both mean always, but vždycky is very common in everyday spoken Czech.

• vždycky = everyday, common, conversational
• vždy = often a bit more formal, literary, or stylistically marked in some contexts

So skoro vždycky sounds very natural here.

You could say skoro vždy, and it would still be understood, but skoro vždycky is the more ordinary choice in speech.