Separable and inseparable prefixes¶

Q: How do you tell a separable prefix from an inseparable one?

By the stress. A separable prefix is stressed: ab-, an-, auf-, aus-, ein-, mit-, nach-, vor-, weg-, zu-, zurück-. In a main clause in the Präsens, it goes to the end (Ich hole dich ab). In a subordinate clause, it stays with the verb (dass ich dich abhole). In the Partizip II ge- comes after it (abgeholt). An inseparable prefix is unstressed: be-, emp-, ent-, er-, ge-, miss-, ver-, zer-. It stays with the verb, and the Partizip II has no ge- (besucht).

Q: When does the Partizip II have no ge-?

ge- comes only before a stressed first syllable. So there is no ge- in verbs with an inseparable prefix (besuchen → besucht, verstehen → verstanden) and in verbs in -ieren (studieren → studiert). In verbs with a separable prefix, ge- comes after the prefix: abholen → abgeholt.

Q: Where does zu go in a verb with a prefix?

With a separable prefix, zu comes between the prefix and the stem: anzurufen, abzuholen. With an inseparable prefix, zu comes before the whole verb: zu besuchen, zu verstehen.

Q: Which prefixes can be separable or inseparable?

Most often über-, um-, durch- and unter-. A verb with such a prefix has one spelling, but its stress and forms depend on the meaning. A stressed prefix separates: umfahren (to knock down) → umgefahren. An unstressed prefix doesn't separate: umfahren (to drive around) → umfahren. In the same way, übersetzen (to ferry across) → übergesetzt, but übersetzen (to translate) → übersetzt.

Compare two verbs with the prefix wieder-:

Er ist gestern wiedergekommen. (He came back yesterday.)
Er hat die Frage wiederholt. (He repeated the question.)

The first Partizip II has ge-, the second doesn't. Learners often write wiedergeholt by analogy with wiedergekommen. But this is a mistake. The difference is whether the prefix separates from the verb. You can see it in the Partizip II, in the word order, and in where zu goes.

Separable prefixes¶

A separable prefix is stressed (the stressed syllable is in bold): wiederkommen, abholen, anrufen. In German, verbs with such a prefix are called trennbare Verben. The prefix behaves like a separate word:

In the Präsens, the Präteritum and the Imperativ, the prefix goes to the end of the sentence: Er kommt morgen wieder. Ich hole dich um acht ab. Hol mich um acht ab!
In a subordinate clause and after a modal verb, the prefix doesn't separate. Here the verb itself is at the end of the sentence, so the prefix has nowhere to go: …, dass er morgen wiederkommt. Ich will dich um acht abholen.
In the Partizip II, ge- comes between the prefix and the stem: wiedergekommen, abgeholt, angerufen.
The particle zu also comes between them: Ich habe vergessen, dich anzurufen.

The most common separable prefixes are ab-, an-, auf-, aus-, ein-, mit-, nach-, vor-, weg-, zu- and zurück-. wieder- almost always separates too: wiederkommen, wiedersehen, wiederfinden.

Inseparable prefixes¶

An inseparable prefix is unstressed: besuchen, verstehen, erklären. In German, verbs with such a prefix are called untrennbare Verben. The prefix never separates from the verb:

In the Präsens, the prefix stays in place: Ich besuche meine Oma.
The Partizip II has no ge-: besucht, verstanden, erklärt.
The particle zu comes before the whole verb: Ich habe keine Zeit, dich zu besuchen.

There are only a few inseparable prefixes, and you can learn them as a list: be-, emp-, ent-, er-, ge-, miss-, ver-, zer-.

The general rule: ge- only before a stressed syllable¶

One rule explains both cases. The Partizip II takes ge- only if the first syllable of the verb is stressed. In abholen, the prefix is stressed, so ge- comes after it: abgeholt. In besuchen, the first syllable is unstressed, so there is no ge-: besucht. The same rule explains why verbs in -ieren have no ge- either. Their stress falls on -ie-: studieren → studiert, telefonieren → telefoniert.

Wiederholen: an inseparable wieder-¶

In wiederholen (to repeat), the stress falls on ho: wiederholen. The prefix wieder- is unstressed here and doesn't separate. This is the only common verb with an inseparable wieder-. So wiederholen works like besuchen, not like wiederkommen:

	wiederholen (to repeat)	wiederkommen (to come back)
Stress	wiederholen	wiederkommen
Präsens	ich wiederhole	ich komme … wieder
Partizip II	wiederholt	wiedergekommen
zu + Infinitiv	zu wiederholen	wiederzukommen

Prefixes that can be separable or inseparable¶

With some prefixes, the stress also changes the meaning of the verb. The most common ones are über-, um-, durch- and unter-. Both verbs have the same spelling, but the stress and the forms differ:

Separable (stressed)	Inseparable (unstressed)
umfahren — to knock down: `Er hat das Schild umgefahren.`	umfahren — to drive around: `Er hat den Stau umfahren.`
übersetzen — to ferry across: `Die Fähre hat uns übergesetzt.`	übersetzen — to translate: `Sie hat den Text übersetzt.`

The same can happen with wieder-. Besides wiederholen (to repeat), there is a rare verb wieder|holen, with the stress on wie. It means "to win back": Der Verein hat sich den Titel wiedergeholt. (The club won the title back.) In many learner's dictionaries, a vertical bar shows that the prefix separates. So wiedergeholt is correct here. But this verb is rare, and people usually say zurückholen instead.