Moje sestra se mě ptá, jestli má na tom rohu jít vlevo, nebo rovně.

Because the full Czech verb is ptát se = to ask. The se is part of the verb itself, not a separate word meaning self in this sentence.

So:

• ptát se = to ask
• ptá se = he/she is asking

Many Czech verbs are built with se or si, and learners usually just need to memorize them as whole units.

Because mě means me, and it shows who is being asked.

So in:

• sestra se mě ptá

the structure is basically:

• sister asks me

With ptát se, the person being asked is put in the case this verb requires. In practice, you can learn the pattern as:

• ptát se někoho = to ask someone

Because mě is the correct form here.

A useful shortcut:

• mě / mne = me
• mně = to me

In this sentence, the verb needs me, not to me, so mě is right.

Also:

• mě is the short, normal everyday form
• mne is a fuller form, often more formal or emphatic
• mně would be wrong here

Here jestli means whether or if in an indirect question.

So:

• ptá se mě, jestli... = she asks me whether/if...

Czech uses jestli very commonly after verbs like:

• ptát se = to ask
• nevědět = not to know
• zjišťovat = to find out

A more formal alternative is zda, but jestli is the normal everyday choice.

Because Czech often leaves out subject pronouns when they are already clear from context.

So:

• jestli má jít vlevo...

literally has no written she, but Czech speakers understand it as:

• whether she should go left...

The verb form má already helps, and the context makes the subject clear. Adding ona would usually be unnecessary unless you wanted extra emphasis.

Here má is not about possession. It is part of the pattern:

• mít + infinitive

This often means:

• should
• is supposed to
• is to

So:

• má jít vlevo = she should go left / she is supposed to go left

This is a very common Czech structure.

For example:

• Mám zavolat? = Should I call?
• Máme čekat? = Are we supposed to wait?

Na tom rohu is in the locative case.

Why?

Because na can take different cases depending on meaning:

• na + locative = location
• na + accusative = movement toward/onto something

Here the meaning is at that corner, so it is location:

• na tom rohu = at that corner

Forms:

• ten → tom
• roh → rohu

Because Czech uses na rohu idiomatically for a street corner or turning point.

So:

• na rohu = at the corner (of a street/intersection)

But:

• v rohu = in the corner (for example, in a room)

Compare:

• Čekám na rohu ulice. = I’m waiting at the street corner.
• Stůl je v rohu pokoje. = The table is in the corner of the room.

Because jít is used for a single movement in one direction, or for choosing a route right now.

That fits this sentence: the sister is asking which way to go at a corner.

• jít = to go, to be going, one specific movement
• chodit = to go regularly / habitually / on foot in general

So:

• má jít vlevo, nebo rovně = should she go left or straight

If you were talking about a repeated habit, chodit would make more sense.

Yes, both are adverbs.

• vlevo = left / to the left
• rovně = straight / straight ahead

They describe the direction of movement.

In route instructions, Czech often uses adverbs like this:

• jít vlevo
• jet rovně
• zahnout doprava

You may also see doleva instead of vlevo. Both can refer to going left, but doleva often feels a bit more like to the left as a direction of turning.

Because jestli má na tom rohu jít vlevo, nebo rovně is a subordinate clause, and Czech separates subordinate clauses with commas.

So the structure is:

• main clause: Moje sestra se mě ptá
• subordinate clause: jestli má na tom rohu jít vlevo, nebo rovně

That is why the comma appears before jestli.

Because nebo here simply joins two alternatives inside the same clause:

• vlevo, nebo rovně

In Czech, you normally do not put a comma before nebo when it just means or between two choices.

The important clause break is before jestli, not before nebo.

Yes. Both mean my sister.

• má sestra = common, short, often the more neutral choice
• moje sestra = also correct, sometimes a bit more emphatic or contrastive

So both are possible. In this sentence, Moje sestra is perfectly natural.

The basic meaning would stay the same, and Czech word order is more flexible than English word order.

This sentence is natural as written:

• Moje sestra se mě ptá, jestli má na tom rohu jít vlevo, nebo rovně.

But Czech can move things around for emphasis or style. For example, the phrase na tom rohu could appear in a slightly different position and still be understandable.

What matters most is:

• ptát se stays together as a verb pattern
• the case forms stay correct
• the sentence keeps a natural information flow

So word order is flexible, but not random.