Learn Hardcore German: Eine kleine Lüge kann später ein großes Problem werden. - A small lie can become a big problem later.

eine kleine Lüge
- eine = feminine nominative indefinite article
- kleine = adjective agreeing with feminine nominative after eine
- Lüge = feminine noun

So:

masculine: ein kleiner Hund (a small dog)
neuter: ein kleines Problem (a small problem)
feminine: eine kleine Lüge (a small lie)

Using ein or kleiner with Lüge would be grammatically wrong, because the gender must match the noun: die Lüge → eine kleine Lüge.

Why is it ein großes Problem and not ein große Problem or ein großer Problem?

Problem is a neuter noun: das Problem.

In the nominative singular with ein (indefinite article) and a neuter noun, the adjective ending is -es:

das Problem → ein großes Problem
- ein = neuter nominative indefinite article
- großes = adjective in neuter nominative after ein
- Problem = neuter noun

Compare:

masculine nominative: ein großer Hund
feminine nominative: eine große Stadt
neuter nominative: ein großes Problem

So ein große Problem (missing the -s) and ein großer Problem (masculine ending) are both incorrect.

What case are eine kleine Lüge and ein großes Problem in?

Both are in the nominative case.

Reason:

The main verb is werden (to become).
In German, the complement of sein (to be) and werden (to become) is in the nominative, not accusative.

So:

Eine kleine Lüge = subject (nominative)
ein großes Problem = predicate noun / complement (also nominative)

Think of the structure as:

Eine kleine Lüge = ein großes Problem (A small lie = a big problem)
The verb phrase kann … werden just adds can become to that idea.

That’s why you don’t see accusative endings here.

What is the function of werden in this sentence? Isn’t werden the future tense?

Werden has two main uses:

As a full verb meaning “to become”:
- Er wird Arzt. – He becomes / is becoming a doctor.
- Das Wetter wird besser. – The weather is getting better.
As an auxiliary verb to form the future tense:
- Er wird kommen. – He will come.

In Eine kleine Lüge kann später ein großes Problem werden, werden is used as a full verb in sense (1): to become.

Literally:
A small lie can later become a big problem.

It is not future tense here; the future idea (“later”) is already covered by später and the meaning of werden = become.

Why do we say kann … werden instead of just wird or kann sein?

Each choice would change the meaning slightly:

kann … werden = can become (focus on development / change over time)
- Eine kleine Lüge kann später ein großes Problem werden.
- Suggests a process: a lie grows into a problem.
wird … (without kann) = will become (more definite prediction)
- Eine kleine Lüge wird später ein großes Problem.
- Sounds like a strong, almost certain statement.
kann … sein = can be (state, not development)
- Eine kleine Lüge kann später ein großes Problem sein.
- Focus on the possibility that at some later point, it is a big problem, not on the process of becoming.

The original sentence wants to stress the development from something small to something big and problematic, so kann … werden is the most natural choice.

Why is später placed between kann and ein großes Problem? Could it go somewhere else?

Yes, später (later) can move around a bit. In the given sentence:

Eine kleine Lüge kann später ein großes Problem werden.

The rule is:

The conjugated verb (kann) is in second position.
The rest of the verb phrase (werden) goes to the end of the clause.
Adverbs like später usually go after the conjugated verb and before the objects/complements, but they are flexible.

Other acceptable versions:

Eine kleine Lüge kann ein großes Problem später werden. (less natural; sounds a bit odd)
Eine kleine Lüge kann ein großes Problem werden, später. (colloquial, with emphasis on “later”)
Später kann eine kleine Lüge ein großes Problem werden. (emphasizes “later”)

The original word order is the most neutral and natural: adverb in the “middle field” (Mittelfeld) after the main verb.

What exactly does später mean here, and how is it different from dann or nachher?

In this sentence, später means “at some later time (in the future)” in a general way.

Differences:

später – later (at a later time), often vague and general:
- Wir reden später. – We’ll talk later (unspecified when).
dann – then, at that moment in time, often linking to something already mentioned:
- Er log, und dann begann das Problem. – He lied, and then the problem began.
nachher – afterwards, after that, often used in spoken language and often more concrete / near future:
- Nachher gehe ich einkaufen. – I’ll go shopping later/afterwards.

In Eine kleine Lüge kann später ein großes Problem werden, später suggests an unspecified future point—not immediately, but at some time down the line.

Why are Lüge and Problem capitalized?

In German, all nouns are capitalized, regardless of position in the sentence.

Lüge and Problem are both nouns, so they must be written with a capital first letter.
This is true even if they are not at the beginning of the sentence.

Examples:

Ich erzähle eine Lüge. – I tell a lie.
Das ist ein Problem. – That is a problem.

Adjectives like kleine and großes are not capitalized (unless they are part of a proper name or used as nouns in special cases, e.g. das Kleine, das Große).

What genders do Lüge and Problem have, and how can I tell?

Lüge is feminine: die Lüge.
- That’s why you see eine kleine Lüge (feminine nominative).
Problem is neuter: das Problem.
- That’s why you see ein großes Problem (neuter nominative).

Unfortunately, the gender of most German nouns is not predictable from the English word. You have to learn the noun together with its article:

die Lüge – the lie (feminine)
das Problem – the problem (neuter)

Some endings give hints (e.g. -ung is usually feminine, -chen usually neuter), but -e and -em aren’t reliable for guessing, so these two are basically “must learn” items.

Why is the verb kann in second position after Eine kleine Lüge? Could the sentence start with Später instead?

German main clauses follow the V2 rule: the conjugated verb must be in second position in the clause.

In the original:

Eine kleine Lüge = first position (the whole phrase counts as one unit)
kann = second position (conjugated verb)
… später ein großes Problem werden = rest of the sentence

You can start with Später to emphasize “later”:

Später kann eine kleine Lüge ein großes Problem werden.

Here:

Später = first position
kann = second
eine kleine Lüge … werden = rest

Both word orders are correct; they just change what is emphasized (subject vs. time).

Is there any difference between groß and großes here?

Yes. Groß is the base form of the adjective (“big”), and großes is that adjective with an ending required by grammar.

In ein großes Problem:

groß- = adjective stem
-es = ending for neuter nominative singular after ein

Adjective endings change with:

gender (masc/fem/neut)
case (nom/acc/dat/gen)
article type (der-word, ein-word, no article)

Compare:

das große Problem – the big problem (definite article, nominative)
ein großes Problem – a big problem (indefinite article, nominative)
kein großes Problem – no big problem

So groß on its own is what you’d see in a dictionary, but in sentences, it almost always gets some ending, like großes, große, großer, großen, etc., depending on the grammar context.