Was unternehmen wir morgen?

In a normal German main question, the finite verb usually comes in second position.
Here, Was is in the first position, so the conjugated verb unternehmen comes next:

• Was
  • unternehmen
    • wir
      • morgen?

So the pattern is:

• Question word
  • verb
    • subject
      • ...

The version Was wir morgen unternehmen? is not the standard word order for a direct question. That kind of order is more like a clause structure you would see inside a larger sentence, for example:

• Ich weiß nicht, was wir morgen unternehmen.
  I don’t know what we’re doing tomorrow.

Here, unternehmen means to do, to undertake, or more naturally in this context, to do something / make plans / engage in an activity.

So Was unternehmen wir morgen? is not just What do we do tomorrow? in a mechanical sense. It usually suggests:

• What are we going to do tomorrow?
• What shall we do tomorrow?
• What do we have planned for tomorrow?

It is often used when talking about activities, outings, or plans.

No. Unternehmen is not separable in this meaning.

That means in the present tense you say:

• Wir unternehmen etwas.
  We’re doing something / undertaking something.

Not:

• Wir nehmen etwas unter. ❌

Its past participle is:

• unternommen

Example:

• Wir haben gestern viel unternommen.
  We did a lot yesterday.

So even though it contains unter-, this verb stays together.

German very often uses the present tense for the future when the time is clear from context.

Since morgen already tells you this is about the future, German does not need a separate future form here.

So:

• Was unternehmen wir morgen?

is completely normal for:

• What are we doing tomorrow?
• What shall we do tomorrow?

German could also use werden for the future, but it is often unnecessary:

• Was werden wir morgen unternehmen?

This is grammatical, but less natural in everyday conversation for a simple planned future.

Here, was is the object of unternehmen, so it is functioning like an accusative object.

Compare:

• Wir unternehmen etwas.
• Was unternehmen wir morgen?

The was is the thing being done.

A helpful way to think about it is:

• We are doing what tomorrow?
• German moves what to the front in the question.

With was, the form does not visibly change the way many nouns or pronouns do, but its role here is the direct object.

Yes, absolutely. Was machen wir morgen? is very common and natural.

The difference is mainly one of nuance:

• Was machen wir morgen? = What are we doing tomorrow?
  Very general, everyday, and common.

• Was unternehmen wir morgen? = What shall we do tomorrow? / What do we have planned?
  Often suggests activities, plans, an outing, or doing something together.

So unternehmen can sound a bit more like what are we going to get up to?

This is a very common and important question.

• morgen = tomorrow
  adverb, so it is written with a lowercase m

• der Morgen = the morning
  noun, so it is written with an uppercase M

In your sentence:

• Was unternehmen wir morgen?
  = What are we doing tomorrow?

If you wrote Morgen with a capital letter in the middle of the sentence, it would normally be understood as the noun morning, which would change the meaning or make the sentence incorrect in context.

Technically, unternehmen can mean undertake, and that is where the dictionary meaning comes from. But in normal conversation, Was unternehmen wir morgen? is much more idiomatic than that.

A native speaker would usually understand it as something like:

• What are we doing tomorrow?
• What do we have planned for tomorrow?
• What shall we do tomorrow?

So while undertake is useful for understanding the verb, it is usually not the best natural translation for this sentence in English.

The structure stays the same: question word + verb + subject + time expression.

Examples:

• Was unternehme ich morgen?
  What am I doing tomorrow?

• Was unternimmst du morgen?
  What are you doing tomorrow?

• Was unternehmt ihr morgen?
  What are you all doing tomorrow?

• Was unternimmt er morgen?
  What is he doing tomorrow?

This is a useful pattern to memorize.

A simple approximate pronunciation is:

• oon-ter-NAY-men

More carefully, the stress is on -neh-:

• un-ter-NEH-men

A few helpful points for English speakers:

• the u in unter- is short
• the e in -nehmen is long and stressed
• the final -en is usually light, not strongly pronounced like English -en

If you want to sound more natural, focus especially on putting the main stress on NEH.

It is neutral and natural in everyday German. It is not especially formal or informal.

You could say it:

• to friends
• to family
• to classmates
• in many normal everyday situations

What changes the level of formality is usually the pronoun and the situation, not this sentence structure itself.

For example, with wir, the sentence is simply a neutral way to ask about shared plans.

Yes. Depending on context, that is often one of the best translations.

If you are discussing plans and deciding together, Was unternehmen wir morgen? can sound like:

• What shall we do tomorrow?
• What are we going to do tomorrow?
• What are we doing tomorrow?

English uses different forms depending on nuance, but German often uses this one simple present-tense question for all of them.