Infinitive, Stem and Endings

1.Infinitive, stem and ending

Three basic concepts matter for almost every later German verb topic:

infinitive → stem + infinitive ending

For example:

lernen → lern- + -en
machen → mach- + -en
sammeln → sammel- + -n

The infinitive is the basic form of the verb. The stem is the part to which endings are added in conjugation. An ending is the changeable part at the end of the form.

lernen, machen and wohnen are infinitives. In simple sentences they then appear as forms such as ich lerne, du machst or wir wohnen.

The main idea at this stage: first learn to see the infinitive and the stem. Then German verb forms become much easier to understand.

Full present-tense conjugation is not explained here yet — this page prepares for it.

2.The infinitive is the basic form of the verb

In a dictionary a German verb normally appears in the infinitive.

• lernen — to learn
• machen — to do / make
• wohnen — to live / reside
• arbeiten — to work
• kommen — to come
• sammeln — to collect

When a new verb is learned, this form is the natural starting point.

dictionary form = infinitive

A dictionary lists lernen, not lerne, lernst or lernt.

The infinitive names an action or state but does not yet show who performs it. The form lernen first expresses only the general idea “to learn”. In a sentence a form that matches the subject appears:

Ich lerne Deutsch.

3.Most infinitives end in -en

The most common infinitive ending is -en.

A useful model:

STEM + -en → infinitive

For example:

lern- + -en → lernen
wohn- + -en → wohnen
spiel- + -en → spielen

4.Some infinitives end only in -n

Not every infinitive ends in -en.

With verbs in -eln and -ern, the infinitive ending in this simple analysis is usefully treated as only -n:

So:

sammeln → sammel- + -n
wandern → wander- + -n

That is why -en should not be stripped automatically from every verb. First check how the infinitive itself ends.

5.What the verb stem is

The stem is the central part of the word that remains recognizable in many forms.

For many simple verbs it can be found like this:

infinitive minus infinitive ending = stem

Examples:

lernen  - en = lern-
machen  - en = mach-
wohnen  - en = wohn-
arbeiten - en = arbeit-
sammeln - n  = sammel-
wandern - n  = wander-

The hyphen in lern- or mach- shows that this is not a complete word, but a word part to which something is added.

6.The stem carries the core lexical meaning

When the ending changes, the stem of a regular verb normally remains easy to recognize.

Take lernen:

infinitive: lernen
stem:       lern-

In conjugation forms such as these appear:

lern-e
lern-st
lern-t
lern-en

The part lern- carries the main lexical meaning. The ending adds grammatical information.

The same principle:

mach-e
mach-st
mach-t

wohn-e
wohn-st
wohn-t

The full ending table does not need to be memorized here yet. What matters is the structure itself:

STEM + ENDING

7.What an ending is

An ending stands at the end of a verb form and can change.

Compare:

lern-e
lern-st
lern-t
lern-en

The stem remains visible:

lern-

The final part changes:

-e
-st
-t
-en

These endings show which subject the verb belongs with.

The full present-tense ending table is treated separately under regular present-tense conjugation.

8.Infinitive and finite form are not the same

Compare:

lernen   = infinitive
lerne    = personal form
lernst   = personal form
lernt    = personal form

The infinitive is the basic form. A personal, or finite, form is adjusted to the subject in the sentence.

That is why, in a simple sentence:

Ich lernen Deutsch.

is not the normal correct form.

Correct:

Ich lerne Deutsch.

At A1 this distinction is enough:

infinitive = basic form
finite form = sentence form that matches the subject

9.A verb can be long and still have a clear stem

Longer verbs are often analyzed by the same principle.

arbeiten  → arbeit- + -en
antworten → antwort- + -en
studieren → studier- + -en
fotografieren → fotografier- + -en

Examples in sentences:

The length of the verb does not change the basic model:

stem + ending

10.Stems ending in -d or -t

Some common verbs have a stem ending in d or t.

arbeiten → arbeit-
reden    → red-
warten   → wart-

The final consonant belongs to the stem.

So not:

arbeiten → arbei-

but:

arbeiten → arbeit-

In some present-tense forms an extra e may be needed after such stems. For now this rule is enough:

When identifying the stem, keep d or t if they stand before the infinitive ending.

11.Verbs in -eln and -ern

These verbs show especially clearly why the infinitive ending can also be -n.

sammeln → sammel- + -n
lächeln → lächel- + -n
wandern → wander- + -n
ändern  → änder- + -n

Here the stem already ends in -el or -er.

Personal forms of such verbs show small special features. Here only the basic analysis of the infinitive matters.

12.Not every stem stays completely unchanged in every form

The model stem + ending is the main starting principle, but some German verbs also change the stem itself.

For example:

fahren → du fährst
lesen  → du liest
nehmen → du nimmst

This does not mean the idea of a stem is wrong. Some verbs simply have a stem-vowel change or other irregular forms. Those changes belong with strong verbs.

On this page the working strategy is:

First see the basic stem.
Add special features later.

13.sein and other highly irregular verbs

Some very common verbs do not fit a simple pattern neatly.

The main example:

sein

Its present-tense forms:

ich bin
du bist
er ist

Here the link to one visibly stable stem is much less regular than with lernen. That is why sein is learned separately. The same applies to other important irregular verbs.

The stem model is a powerful tool, but it does not mean that every German verb is completely regular.

14.Three levels when learning a verb

When learning a verb it helps to keep three levels separate:

As a model:

lernen
↓
lern- + -en
↓
lern- + new ending
↓
lerne / lernst / lernt ...

This is the bridge from the dictionary form to conjugation. The central formula of the topic:

INFINITIVE
↓
STEM + INFINITIVE ENDING
↓
STEM + PERSONAL ENDING
↓
VERB FORM IN THE SENTENCE

15.How to analyze a new simple infinitive

With a new regular verb, four steps can be walked through mentally.

Step 1: Find the infinitive

wohnen

Step 2: Find the infinitive ending

-en

Step 3: Identify the stem

wohn-

Step 4: See what happens next

wohn- + personal ending

For example, then this appears:

Ich wohne hier.

The purpose of such analysis is not to cut words mechanically, but to make conjugation understandable.

16.Connection to the sentence core

The core of a German statement:

subject + personal verb form

Now it is clearer where that verb form comes from.

infinitive: lernen
stem:       lern-
form:       lern- + -e → lerne

This gives:

Ich lerne.

Or:

infinitive: wohnen
stem:       wohn-
form:       wohn- + -t → wohnt

Paul wohnt in Bonn.

That is how word structure connects to sentence structure.

17.Typical mistakes

Confusing the infinitive and the stem

lernen = stem

is wrong.

Correct:

lernen = infinitive
lern-  = stem

Removing only -n from every verb

That would incorrectly give lerne- from lernen.

Correct:

lernen → lern- + -en

With -n verbs:

sammeln → sammel- + -n

Dropping the final stem consonant

Incorrect: arbeiten → arbei-. Correct: arbeiten → arbeit-.

Using the infinitive unchanged as a personal form

Incorrect: Ich lernen Deutsch.. Correct: Ich lerne Deutsch..