Wanneer kan jy?

• Wanneer = when
• kan = can / be able to
• jy = you (informal singular, and often used in everyday speech)

So word-for-word, it is When can you?

In natural use, it often really means something like:

• When can you come?
• When are you available?
• When can you do it?

The exact meaning depends on the context.

Yes, for a full literal idea, you might expect another verb, such as:

• Wanneer kan jy kom? = When can you come?
• Wanneer kan jy help? = When can you help?

But in conversation, Afrikaans can leave out the final verb if it is already obvious from context. So Wanneer kan jy? is a shortened, natural spoken question when both speakers already know what action is being talked about.

English can do something similar in conversation, but Afrikaans uses this kind of ellipsis quite comfortably.

Because Afrikaans uses normal question word order here:

• Wanneer = question word
• kan = finite verb
• jy = subject

So in a direct question, the finite verb comes before the subject after the question word:

• Wanneer kan jy?

This is similar to:

• Waar woon jy? = Where do you live?
• Hoekom kom hy? = Why is he coming?

Wanneer jy kan would not be a normal standalone question. It would more likely be part of a longer sentence, such as:

• Kom wanneer jy kan. = Come when you can.

Kan usually means can or be able to.

In this sentence, it can express:

• ability
• possibility
• availability, depending on context

For example, Wanneer kan jy? often really asks about someone’s availability:

• When are you free?
• When would suit you?

So even though kan literally means can, in real conversation it may feel closer to When are you available?

Jy is the normal informal word for you.

If you want to be formal or very polite, Afrikaans can use u:

• Wanneer kan u?

That said, jy is extremely common in everyday Afrikaans, and Afrikaans generally uses formal u less often than some other languages use their formal you forms.

A simple learner-friendly guide is:

• Wanneer ≈ vuh-NEH-er or vuh-NEER depending on accent
• kan ≈ kun with a short a
• jy ≈ yay / yei (not exactly English you)

A rough full pronunciation:

• vuh-NEH-er kun yei?

A few useful notes:

• w in Afrikaans is pronounced more like English v
• g is not present here, so this sentence is easier to say than many Afrikaans ones
• jy does not sound like English gee or jai

Yes, in conversation it can be natural, especially when the missing action is obvious.

For example:

• Ek wil jou sien. Wanneer kan jy? = I want to see you. When can you?
  More naturally: When are you free?

Still, if there is no context, it may sound incomplete. In that case, speakers would often say the full version:

• Wanneer kan jy kom?
• Wanneer kan jy ontmoet?
• Wanneer kan jy dit doen?

So it is natural, but strongly context-dependent.

Usually, no. In most cases kan is about ability or practical possibility, not permission.

If you want to express may in the sense of permission, Afrikaans often uses mag:

• Wanneer mag jy? = When are you allowed to?

So:

• kan = can / be able to
• mag = may / be allowed to

You can answer with a time or day, for example:

• Ek kan môre. = I can tomorrow.
• Ek kan om drie-uur. = I can at three o’clock.
• Ek kan volgende week. = I can next week.
• Ek kan nie vandag nie. = I can’t today.

If you want to be fuller:

• Ek kan môre kom. = I can come tomorrow.
• Ek kan jou Vrydag help. = I can help you on Friday.

Yes. Wanneer is jy beskikbaar? means When are you available? and is more explicit.

Compare:

• Wanneer kan jy? = shorter, context-based, conversational
• Wanneer is jy beskikbaar? = clearer and more direct about availability

Both are useful, but Wanneer kan jy? depends more on the listener already knowing what is being discussed.