Learn Hardcore German: Ich lege den Elternbrief auf den Küchentisch. - I put the parent letter on the kitchen table.

Elternbrief is masculine (more on that below).
The definite article for a masculine noun changes like this:
- Nominative (subject): der Elternbrief
- Accusative (direct object): den Elternbrief

In this sentence:

Ich = subject (nominative)
lege = verb
den Elternbrief = direct object (accusative)

So den is required here, not der.

How do I know that Elternbrief is masculine?

The noun Elternbrief is a compound noun: Eltern (parents) + Brief (letter).

In German compounds, the last part decides:

the basic meaning
the gender
the plural form

Here, the last part is Brief, which is:

der Brief (masculine)
plural: die Briefe

So the compound becomes:

der Elternbrief (masculine)
plural: die Elternbriefe

That’s why you get den Elternbrief in the accusative.

Why is it auf den Küchentisch and not auf dem Küchentisch?

Because auf is a two-way preposition (Wechselpräposition). With such prepositions, the case depends on meaning:

Accusative = movement to a place (answering wohin? = to where?)
Dative = location at a place (answering wo? = where?)

Compare:

Ich lege den Elternbrief auf den Küchentisch.
→ movement onto the table (wohin?) → accusative → den Küchentisch
Der Elternbrief liegt auf dem Küchentisch.
→ already lying on the table (wo?) → dative → dem Küchentisch

So here, the action is putting the letter onto the table, so auf den Küchentisch (accusative) is correct.

Why is it den Küchentisch and not der Küchentisch?

Same reason as with den Elternbrief: Küchentisch is also a masculine noun in the accusative case.

Base form: der Küchentisch (masculine)
In accusative singular (as object of the preposition auf indicating movement): den Küchentisch

Only the article changes; the noun Küchentisch itself stays the same in the accusative:

Nominative: der Küchentisch
Accusative: den Küchentisch

Why is Küchentisch written as one word and not Küche Tisch?

German often combines nouns into one long compound word.

Küche = kitchen
Tisch = table
Küchentisch = kitchen table (a particular kind of table)

Rules/points:

Compound nouns are written together as one word.
The last part determines:
- gender: der Tisch → der Küchentisch
- plural: die Tische → die Küchentische
The first part (Küchen-) describes what kind of table it is.

Writing Küche Tisch would be wrong in standard German; it must be Küchentisch.

What is the difference between legen and liegen?

They form an action vs state pair:

legen = to lay/put something down (you do it to an object)
- needs an object (transitive)
- Ich lege den Elternbrief auf den Küchentisch.
  I put/lay the parents’ letter on the kitchen table.
liegen = to lie, to be lying (describes the position of something)
- no direct object
- Der Elternbrief liegt auf dem Küchentisch.
  The parents’ letter is lying on the kitchen table.

Many German verbs of position work like this:

legen ↔ liegen (lay vs lie)
stellen ↔ stehen (set/stand vs stand)
setzen ↔ sitzen (seat vs sit)

How is legen different from stellen and setzen?

They all mean some kind of put/position but differ by the final position:

legen: put something so that it lies (usually horizontal)
- Ich lege das Buch auf den Tisch. (The book will be lying.)
stellen: put something so that it stands (upright/vertical, on its base)
- Ich stelle das Glas auf den Tisch. (The glass will be standing.)
setzen: seat someone / make someone sit
- Ich setze das Kind auf den Stuhl. (The child will be sitting.)

In your sentence, Elternbrief is something that will be lying flat, so legen is the natural choice.

Can I change the word order, for example: Auf den Küchentisch lege ich den Elternbrief?

Yes, German word order is more flexible than English, as long as you respect the verb in 2nd position rule in main clauses.

All of these are grammatically correct, with different emphasis:

Ich lege den Elternbrief auf den Küchentisch.
(Neutral, most typical order.)
Den Elternbrief lege ich auf den Küchentisch.
(Emphasizes den Elternbrief.)
Auf den Küchentisch lege ich den Elternbrief.
(Emphasizes auf den Küchentisch — the place.)

What you cannot do is move the finite verb out of second position, e.g.:

✗ Ich den Elternbrief auf den Küchentisch lege. (wrong in normal main clause)

Can I leave out Ich like in English “Put the letter on the kitchen table”?

Not in a normal statement. German usually requires the subject pronoun.

Statement: Ich lege den Elternbrief auf den Küchentisch.
(I put the letter on the kitchen table.)

If you want an imperative (a command), you change the form of the verb, not by dropping ich:

Leg den Elternbrief auf den Küchentisch! (informal du)
Legen Sie den Elternbrief auf den Küchentisch! (formal Sie)
Legt den Elternbrief auf den Küchentisch! (plural ihr)

So: subject pronouns are normally not dropped in German, unlike in Spanish or Italian.

Why is it ich lege and not something like ich legt?

Because legen is a regular verb, and it is conjugated in the present tense.

For legen, the present tense forms are:

ich lege
du legst
er/sie/es legt
wir legen
ihr legt
sie legen

So with ich, you add -e: ich lege.
The form legt goes with er/sie/es or ihr, not with ich.

Could I also say Ich habe den Elternbrief auf den Küchentisch gelegt?

Yes, that is the present perfect (Perfekt) and is very common in spoken German:

Ich lege den Elternbrief auf den Küchentisch.
→ either happening right now or a general/near-future statement.
Ich habe den Elternbrief auf den Küchentisch gelegt.
→ emphasizes that the action is completed in the past.

In many everyday contexts, German prefers Perfekt for past actions (ich habe gelegt) rather than Präteritum (ich legte), except in more formal written language.

Could I say Ich lege den Elternbrief auf den Tisch in der Küche instead of auf den Küchentisch?

Yes, you can:

Ich lege den Elternbrief auf den Küchentisch.
→ specifically the kitchen table.
Ich lege den Elternbrief auf den Tisch in der Küche.
→ the table in the kitchen (could imply there’s more than one table overall, but this one is located in the kitchen).

Both are correct. Küchentisch is just a compact compound noun for kitchen table.