Learn Hardcore German: Morgen treffe ich meinen Sprachpartner im Café, um die neue Grammatik zu üben. - Tomorrow I am meeting my language partner at the café in order to practice the new grammar.

No, it is not required. German main clauses follow the verb‑second (V2) rule: the conjugated verb must be in second position, but almost any one element can come first.

In your sentence:

Morgen = element 1
treffe = element 2 (the verb)
ich = element 3

You could also say:

Ich treffe morgen meinen Sprachpartner im Café, um die neue Grammatik zu üben.
Im Café treffe ich morgen meinen Sprachpartner, um die neue Grammatik zu üben.

All of these are correct. Starting with Morgen simply emphasizes the time (“Tomorrow, I’m meeting…”), but the basic meaning is the same.

Why is Morgen capitalized? Is it the same word as morgen = “tomorrow”?

At the beginning of a sentence, the first word is always capitalized, so you cannot tell from spelling alone whether it is:

morgen (adverb) = tomorrow
der Morgen (noun) = the morning

In this sentence, the intended meaning is “tomorrow”, so grammatically it is the adverb morgen, just written with a capital M because it is the first word.

To say “in the morning,” you would usually say:

Am Morgen treffe ich meinen Sprachpartner im Café. = In the morning, I’m meeting my language partner in the café.

Why is it treffe and not something like werde treffen to talk about the future?

German very often uses the present tense to talk about the future, especially when there is a time expression like morgen, nächste Woche, bald, etc.

Morgen treffe ich meinen Sprachpartner. = I’m meeting my language partner tomorrow.
Nächste Woche fahre ich nach Berlin. = I’m going to Berlin next week.

You can use werden + infinitive for the future:

Morgen werde ich meinen Sprachpartner treffen.

This is also correct, but in everyday German the simple present tense with a time word is more common and sounds more natural here.

Why is it meinen Sprachpartner and not mein Sprachpartner?

Sprachpartner is the direct object of the verb treffen (you are “meeting someone”), so it has to be in the accusative case.

Nominative (subject): mein Sprachpartner
Accusative (direct object): meinen Sprachpartner

Pattern for a masculine noun with mein:

mein Sprachpartner – my language partner (subject)
ich treffe meinen Sprachpartner – I meet my language partner (object)

So meinen tells you this is the object, not the subject.

Why is Sprachpartner masculine? How do I say it if my partner is female, or if there are several partners?

By default, Sprachpartner is a masculine noun:

Singular masculine: der Sprachpartner
Plural (mixed or all-male group): die Sprachpartner

For a specifically female partner, German uses a feminine form:

Singular feminine: die Sprachpartnerin
Plural feminine: die Sprachpartnerinnen

So you could also say:

Morgen treffe ich meine Sprachpartnerin im Café… (one female partner)
Morgen treffe ich meine Sprachpartner im Café… (several partners, mixed or all-male)
Morgen treffe ich meine Sprachpartnerinnen im Café… (several female partners)

Why is it im Café and not in dem Café or ins Café?

im is simply the contracted form of in dem:

in
- dem → im

So:

im Café = in dem Café = in the café

Both are correct, but im is far more common in normal speech and writing.

You do not use ins here because:

ins = in das (accusative) and usually describes movement into something:
- Ich gehe ins Café. = I am going into the café.

In your sentence, im Café describes where the meeting takes place (location, no movement), so you use in + dative → im Café.

How do you pronounce Café, and why does it have an accent?

Café is a loanword from French, and the accent is kept in German spelling.

Pronunciation in German:

Ca- like ka in Kaffee
-fé with stress on the second syllable, like feh
Together: ka-FEH

The accent mainly reminds you to stress the last syllable and to pronounce the final e as a vowel, not as silent (unlike many English words ending in -e).

Like all German nouns, Café is capitalized:

das Café = the café

Why is there a comma before um?

The part um die neue Grammatik zu üben is an infinitive clause of purpose (“in order to practise the new grammar”).

In German, infinitive clauses with um … zu, ohne … zu, anstatt … zu are normally set off by a comma:

Ich lerne jeden Tag, um besser Deutsch zu sprechen.
Er ging weg, ohne ein Wort zu sagen.

So the comma marks the beginning of this purpose clause, which depends on the main clause.

What exactly does the structure um … zu üben mean? Can I leave out um or zu?

um … zu + infinitive expresses purpose and usually translates as “in order to …”.

In your sentence:

Main clause: Morgen treffe ich meinen Sprachpartner im Café
Purpose clause: um die neue Grammatik zu üben
Meaning: I’m meeting my language partner in the café in order to practise the new grammar.

About um and zu:

You cannot drop zu in standard German in this structure; üben must be in the zu‑infinitive form: zu üben.
You normally also keep um; if you drop um, the sentence becomes grammatical but less clear as a purpose clause and sounds off in standard written German.

So the natural, standard form is um … zu + infinitive.

Why is it die neue Grammatik here, and why does neue end in -e?

Grammatik is a feminine noun:

Nominative singular: die Grammatik
Accusative singular: die Grammatik

In the infinitive clause, die neue Grammatik is the object of üben, so it is in the accusative singular feminine:

Article: die (feminine accusative singular)
Adjective: neue
Noun: Grammatik

With a definite article like die, the adjective takes the weak ending -e in the feminine singular:

die neue Grammatik
die alte Grammatik
die schwierige Übung

So die neue Grammatik is exactly the expected form: the new grammar as an object.

Could I change the word order to Ich treffe morgen meinen Sprachpartner im Café, um die neue Grammatik zu üben? Does that change the meaning?

Yes, that word order is completely correct, and the meaning does not change in any important way.

Possible variants include:

Ich treffe morgen meinen Sprachpartner im Café, um die neue Grammatik zu üben.
Morgen treffe ich meinen Sprachpartner im Café, um die neue Grammatik zu üben.
Morgen treffe ich im Café meinen Sprachpartner, um die neue Grammatik zu üben.
Im Café treffe ich morgen meinen Sprachpartner, um die neue Grammatik zu üben.

The differences are mainly in emphasis (what you put first), not in basic meaning:

First position stresses time (Morgen), place (Im Café), or subject (Ich).

What is the difference between treffen, sich treffen, and kennenlernen here?

All three relate to “meeting,” but they are used differently:

treffen (+ Akkusativ)
- Focus: you meet someone (you go to them / encounter them).
- Example: Morgen treffe ich meinen Sprachpartner.
- Similar to English “I’m meeting my language partner” or “I’m going to meet him.”
sich treffen (mit + Dativ)
- Reflexive: two or more people arrange to meet each other.
- Example: Morgen treffe ich mich mit meinem Sprachpartner im Café.
- That clearly means “we are meeting each other,” like English “I’m meeting up with my language partner.”
kennenlernen
- Focus: getting to know someone for the first time.
- Example: Morgen lerne ich meinen neuen Sprachpartner kennen.
- That means “Tomorrow I’ll meet my new language partner for the first time / get to know him.”

In your sentence, treffe is fine and natural if the partner is someone you already know.

Could I also say Morgen werde ich meinen Sprachpartner im Café treffen, um die neue Grammatik zu üben? Does it sound different?

Yes, that sentence is grammatically correct:

Morgen werde ich meinen Sprachpartner im Café treffen… = Tomorrow I will meet / am going to meet my language partner in the café…

Difference in feeling:

Present tense + time word (Morgen treffe ich …) is normal, everyday German for planned future actions.
Futur I (werde treffen) can sound slightly more formal or can be used if you want to emphasize the future aspect or make a prediction.

In most casual contexts, Germans would prefer:

Morgen treffe ich meinen Sprachpartner im Café…