
wiederholen
to repeat
To say, write, or do something again. This verb is not separable.
Könnten Sie die Frage bitte wiederholen? Ich habe sie nicht verstanden.
Could you please repeat the question? I didn't understand it.
to repeat / retrieve
Loading your saved state.

to repeat
To say, write, or do something again. This verb is not separable.
Könnten Sie die Frage bitte wiederholen? Ich habe sie nicht verstanden.
Could you please repeat the question? I didn't understand it.

to repeat itself
When an event, pattern, or situation occurs again.
Die Geschichte neigt dazu, sich zu wiederholen.
History tends to repeat itself.

to review
To go through learning material or something already learned again in order to reinforce it.
Vor der Prüfung müssen wir das letzte Kapitel wiederholen.
Before the exam, we have to review the last chapter.

to retrieve
To fetch back or get back something that you gave away or lost. This verb is separable, e.g. 'er holt es wieder' (he gets it back).
Er ging zurück, um seinen vergessenen Schirm wiederzuholen.
He went back to retrieve his forgotten umbrella.
This word has two variants with different meanings and grammar. The inseparable verb 'wiederholen' (stress on '-ho-') means 'to do/say something again'. The separable verb 'wieder holen' (stress on 'wie-') means 'to fetch something back'.
Er wiederholt die Klasse. (untrennbar: Er macht die Klasse nochmal)
He is repeating the grade. (inseparable: He is doing the grade again)
In the meaning 'to say or do something again', 'wiederholen' (to repeat) is always inseparable. The prefix 'wieder-' stays firmly attached to the verb in all sentence forms.
Ich habe seinen Namen nicht wiederholt.
I did not repeat his name.
When an event or pattern occurs again by itself, the reflexive form 'sich wiederholen' (to repeat itself) is used. The subject is then the event itself.
Solche Fehler dürfen sich nicht wiederholen.
Such mistakes must not repeat themselves.
In the context of learning, 'wiederholen' (to review/repeat) is often combined with learning content. Typical objects are vocabulary, grammar, a chapter, or the course material.
Vor dem Test wiederhole ich immer alle wichtigen Vokabeln.
Before the test, I always review all the important vocabulary.
When 'wiederholen' means 'zurückholen' (to fetch back), it is separable. The particle 'wieder' stands at the end in a main clause. In the infinitive, it is written as one word: 'wiederzuholen' (to retrieve).
Er musste umkehren, um seine Jacke wiederzuholen.
He had to turn around to retrieve his jacket.
to renew
Wiederholen means neutrally expressing a demand or statement again. Erneuern also means putting it forward again, but emphasizes its insistence. If you only mean saying the demand again, use wiederholen; if you are asserting the demand more forcefully again, use erneuern.

Die Beschäftigten wiederholen ihre Forderung nach kürzeren Arbeitszeiten.
The employees repeat their demand for shorter working hours.
Nach den erfolglosen Gesprächen erneuern die Beschäftigten ihre Forderung nach kürzeren Arbeitszeiten.
After the unsuccessful talks, the employees renew their demand for shorter working hours.