Learn Hardcore German: Heute Abend gehe ich mit meiner Freundin aus. - This evening I am going out with my friend.

In German main clauses, the conjugated verb must be in second position (the “V2 rule”).
Here, Heute Abend (Today/This evening) is put in first position for emphasis, so the verb gehe has to come second, and the subject ich comes after it:

Heute Abend (1st position) gehe (2nd) ich (3rd) …

If you don’t move anything to the front, you get the more “neutral” order: Ich gehe heute Abend mit meiner Freundin aus.

Can I also say Ich gehe heute Abend mit meiner Freundin aus instead?

Yes, that sentence is completely correct and very common.

Ich gehe heute Abend … is a neutral word order.
Heute Abend gehe ich … puts a bit more emphasis on when you’re going out, similar to English: “This evening I’m going out with my girlfriend.”

Both are natural; Germans use both all the time.

Why is Abend capitalized, but heute is not?

In German, all nouns are capitalized, regardless of where they appear in the sentence.

Abend is a noun (evening) → Abend
heute is an adverb (today) → heute

So: heute Abend, with only Abend capitalized.

Why is it mit meiner Freundin and not mit meine Freundin?

The preposition mit in German always takes the dative case.
The feminine dative form of meine (my) is meiner, and Freundin is a feminine noun.

So:

Nominative: meine Freundin (my girlfriend/female friend)
Dative (after mit): mit meiner Freundin

Other common dative-preposition examples: mit, bei, nach, seit, von, zu, aus, außer all require dative.

How would the phrase change if I’m talking about a male friend/ boyfriend?

The masculine form of Freundin is Freund. In the dative singular, the possessive changes too:

Masculine nominative: mein Freund (my (boy)friend)
Masculine dative (after mit): mit meinem Freund

So the sentence would be:
Heute Abend gehe ich mit meinem Freund aus.

Does Freundin mean “friend” or “girlfriend”?

Freundin can mean either female friend or girlfriend; context decides.

However, there’s a strong tendency:

meine Freundin usually means my girlfriend in adult contexts.
To stress “just a friend”, people often say eine Freundin von mir (a female friend of mine) or add extra explanation.

So in this sentence, mit meiner Freundin ausgehen will typically be understood as “with my girlfriend” unless context clearly says otherwise.

Why is aus at the end of the sentence?

Ausgehen is a separable verb: aus- (prefix) + gehen (to go).
In main clauses, the conjugated part (gehe) goes in second position, and the separable prefix (aus) goes to the end of the clause:

Infinitive: ausgehen
Main clause: Ich gehe … aus.

So: Heute Abend gehe ich mit meiner Freundin aus.

When do I use ausgehen as one word instead of splitting it?

You keep it together as ausgehen (one word) in:

Infinitive form:
- Ich möchte heute Abend ausgehen. (I want to go out this evening.)
Subordinate clauses, where the verb moves to the end:
- … weil ich heute Abend mit meiner Freundin ausgehe.
- … dass wir heute Abend ausgehen.

In a normal main clause like your example, you split it: gehe … aus.

Can I just say Heute Abend gehe ich mit meiner Freundin and leave out aus?

You can say it, but the meaning changes.

mit meiner Freundin gehen = just go/walk with her (no clear “going out socially” meaning).
mit meiner Freundin aus(gehen) = go out in the social sense (to a bar, for dinner, etc.).

Without aus, listeners won’t automatically think of “going out on a date” or for entertainment; it’s just going somewhere together.

Can I say Heute Abend werde ich mit meiner Freundin ausgehen instead of gehe ich … aus?

Yes, that’s grammatically correct:
Heute Abend werde ich mit meiner Freundin ausgehen.

But in everyday German, the present tense is usually used to talk about the (near) future, especially with a time expression like heute Abend:

Heute Abend gehe ich … ≈ “I’m going (out) this evening.”

Using werde … ausgehen sounds a bit more formal or emphatic, or like you’re planning/announcing it, but it’s not wrong.

What’s the difference between heute Abend and heute Nacht?

heute Abend = this evening (roughly until late evening, before you’d naturally say “night”).
heute Nacht = tonight / during the night (late night hours, while people normally sleep).

So Heute Abend gehe ich … aus suggests an evening activity (dinner, drinks, cinema), not something in the middle of the night.

Why do we say heute Abend and not something like dieser Abend for “this evening”?

The standard idiomatic way to say “this evening” in German is heute Abend (literally “today evening”).

dieser Abend is grammatically possible, but it is rarely used in this time-meaning. It’s more likely to appear when you are talking about “this particular evening” as an event, e.g. in a narrative:
- Dieser Abend war unvergesslich. (That evening was unforgettable.)

For planning/announcing: heute Abend is what you want.

How do I pronounce Freundin, especially the eu?

eu in German is pronounced like the English “oy” in “boy”.
Freundin sounds roughly like “FROYND-in” (but with a German r, not a strong English r).

Syllables: Freund (like “froynd”) + -in.
Also note the stress: FREUndin → stress on the first syllable.

How is ich pronounced? I’ve heard different versions.

Ich has a sound that doesn’t exist in standard English, the so‑called “ich‑Laut”:

The ch is a soft, hissing sound made with the tongue close to the palate, not like English “k” or “ch” in “chair”.
A rough approximation for English speakers is something like “ish”, but with the tongue closer to the roof of the mouth and more breathy.

In careful standard German, ich never sounds like “ick”; “ick” is a regional variant (e.g. in some Berlin dialects).

Is there a difference between ausgehen and weggehen in this kind of sentence?

Yes, there’s a nuance:

ausgehen = go out socially, for leisure/entertainment (date, bar, restaurant, party).
- Heute Abend gehe ich mit meiner Freundin aus. → We’re going out (on a date / for fun).
weggehen = go away / leave a place; it focuses more on leaving, not on the social activity.
- Ich gehe jetzt mit meiner Freundin weg. → I’m leaving now with my girlfriend.

Both can sometimes overlap, but ausgehen is the standard verb for “to go out” in the sense of social/romantic outing.