Present Tense: Strong Verbs with a to ä, au to äu, o to ö | German Grammar

A second family of strong verbs marks the present tense not by switching to a new vowel but by adding an umlaut: a → ä, and more rarely au → äu and o → ö. As with the e → i verbs, the change is tightly localized: it hits only the du and er/sie/es forms. Every other person keeps the plain, un-umlauted vowel. That makes the pattern doubly predictable — you know which vowels can change, and you know exactly where.

The pattern: umlaut in two cells

Take fahren (to drive, to go by vehicle). The stem vowel a gets two dots — ä — but only in the du and er forms:

Person	Form	Vowel
ich	fahre	a (plain)
du	fährst	a → ä
er / sie / es	fährt	a → ä
wir	fahren	a (plain)
ihr	fahrt	a (plain)
sie / Sie	fahren	a (plain)

The endings are entirely regular (-e, -st, -t, -en, -t, -en). Only the vowel of du and er/sie/es gets the umlaut. The umlaut is obligatory, not stylistic: du fahrst is simply wrong, the way "he go" is wrong in English.

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Only back vowels can take this umlaut: a, au, o. A verb with e, i, or u in its stem will never umlaut this way (the e-verbs change by a different route, e → i/ie). So the change is doubly constrained: only a/au/o can change, and only in the 2nd and 3rd person singular. If you train those two cells, you have the whole pattern.

Fährst du dieses Jahr wieder nach Italien?

Are you driving to Italy again this year? (informal)

Der Bus fährt leider erst in einer Stunde.

Unfortunately the bus doesn't leave for another hour.

a becomes ä

This is by far the largest group. Here are the most common verbs, with the ich form (plain) beside the du / er forms (umlauted).

Infinitive	Meaning	ich	du	er / sie / es
fahren	to drive, go (by vehicle)	fahre	fährst	fährt
schlafen	to sleep	schlafe	schläfst	schläft
tragen	to carry, to wear	trage	trägst	trägt
fallen	to fall	falle	fällst	fällt
halten	to hold, to stop	halte	hältst	hält
waschen	to wash	wasche	wäschst	wäscht
wachsen	to grow	wachse	wächst	wächst
schlagen	to hit, to beat	schlage	schlägst	schlägt
raten	to advise, to guess	rate	rätst	rät
lassen	to let, to leave	lasse	lässt	lässt

Schläfst du noch oder bist du schon wach?

Are you still asleep or are you awake already? (informal)

Sie trägt heute den grünen Mantel.

She's wearing the green coat today.

Vorsicht, das Glas fällt gleich runter!

Careful, the glass is about to fall! (informal)

The t/d-rule meets the umlaut

Two of these verbs — halten and raten — have stems ending in -t. Normally a stem in -t or -d inserts an extra -e- before consonant endings (so a weak verb like arbeiten gives du arbeitest, er arbeitet). But strong verbs with an umlaut skip that extra -e- in the er form: the third person is simply er hält, er rät — not er haltet, not er ratet. The du form keeps the -st directly too: du hältst, du rätst.

Der Zug hält an jedem Bahnhof.

The train stops at every station.

Rätst du jetzt einfach, oder weißt du es?

Are you just guessing now, or do you actually know? (informal)

This collision with the t/d-rule is one of the few genuinely fiddly points here — there is no elegant logic to it, so the safest move is to memorize er hält and er rät as fixed forms.

au becomes äu, o becomes ö

These two sub-patterns cover only a handful of verbs, but they are common ones.

Infinitive	Meaning	ich	du	er / sie / es
laufen	to run, to walk	laufe	läufst	läuft
saufen	to booze (informal/coarse)	saufe	säufst	säuft
stoßen	to push, to bump	stoße	stößt	stößt

Note stoßen: the stem already ends in -ß, so the du form merges into -ßt — du stößt — identical to the er form. And the ß is correct after the long ö; it does not become ss.

Wie schnell läufst du die zehn Kilometer?

How fast do you run the ten kilometers? (informal)

Pass auf, du stößt gleich an den Tisch!

Watch out, you're about to bump into the table! (informal)

Mein Hund läuft jeden Morgen mit mir im Park.

My dog runs with me in the park every morning.

The imperative does NOT take the umlaut

Here is a subtle but important difference from the e → i verbs. With e → i verbs, the du-imperative borrows the changed vowel (gib!, nimm!). But with the umlaut verbs, the imperative drops the umlaut and uses the plain vowel: from du fährst the command is Fahr! (not Fähr!), from du schläfst it is Schlaf!, from du läufst it is Lauf!

Fahr bitte langsamer, hier sind Kinder.

Please drive slower, there are children here. (informal command)

Lauf nicht so schnell, ich komme nicht mit!

Don't run so fast, I can't keep up! (informal command)

So the rule splits neatly: e-verbs keep their vowel change in the imperative; a/au/o-verbs drop the umlaut.

How this differs from English

English has nothing comparable. English present-tense verbs never add an accent or change their vowel quality; the third person just gains an -s ("she drives," "he sleeps"). Because there is no English habit to recruit, the umlaut feels like an arbitrary decoration to learners — and the single most common error is simply forgetting it. It helps to hear the umlaut as a real, audible vowel shift: fahre has the broad open a of "father," while fährt has the tighter ä closer to the e in "bed." Once you can hear the difference, leaving it off will start to sound wrong to your own ear.

Common Mistakes

❌ Du fahrst zu schnell.

Incorrect — the du form needs the umlaut: fährst.

✅ Du fährst zu schnell.

You're driving too fast.

❌ Er schlaft schon.

Incorrect — missing umlaut; the er form is schläft.

✅ Er schläft schon.

He's already asleep.

❌ Wir fähren morgen los.

Incorrect — wir keeps the plain vowel: fahren.

✅ Wir fahren morgen los.

We're setting off tomorrow.

❌ Der Zug haltet hier nicht.

Incorrect — strong verb skips the extra -e-: er hält.

✅ Der Zug hält hier nicht.

The train doesn't stop here.

❌ Fähr bitte vorsichtig!

Incorrect — the imperative drops the umlaut: Fahr!

✅ Fahr bitte vorsichtig!

Please drive carefully. (informal command)

Key Takeaways

The umlaut (a → ä, au → äu, o → ö) appears only in du and er/sie/es — the same two cells as the e → i change.
Only back vowels (a, au, o) can umlaut; e/i/u stems never do.
The umlaut is obligatory: du fahrst and er schlaft are errors, not casual variants.
halten and raten override the t/d-rule: er hält, er rät (no extra -e-).
Unlike e-verbs, these verbs drop the umlaut in the imperative: Fahr!, Schlaf!, Lauf!

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