Difference between "zweifeln", "anzweifeln" and "bezweifeln"

Question

I was looking at the verb form from the word "Zweifel" and I found 3 different words:

• zweifeln
• anzweifeln
• bezweifeln

It probably is subtle, but could someone explain me the difference between them, and where I can and can not use them in context?

Answer 1

There are indeed very subtle differences in both meaning and usage.

Something that hasn't been mentioned here before: you can use zweifeln without any object at all:

Ich zweifle.

would be possible to say and is as general as Ich denke. or Ich glaube.

Another example:

Glaubst Du nun endlich an die Auferstehung? Nein, ich zweifle immer noch.

You can also use zweifeln with a relative clause starting with ob to express having doubts about some decision or move:

Ich zweifle, ob ich ihm glauben soll.

In all these examples you could not use anzweifeln or bezweifeln instead.

Anzweifeln and bezweifeln can both have a direct object. With zweifeln you would use the preposition an in these cases. Bezweifeln and zweifeln can be followed by a relative clause. With zweifeln you may insert daran, then.

Niemand zweifelte [daran], dass es gelingen würde.

(example taken from the Duden)

For the differences in meaning I think it's worthwhile pointing out the difference between having doubts and expressing doubts. Anzweifeln always implies the latter. That's why you cannot use it instead of zweifeln in

Sie sah mich an, als zweifle sie an meinem Verstand.

(same source)

zweifeln is more often used for having doubts and bezweifeln for expressing doubts (in particular you can say Ich bezweifle, dass ... to express you are having doubts ;-)), but (often) you can use both of them for the other, too. Let's look again at

Niemand zweifelte [daran], dass es gelingen würde.

This would rather mean nobody having doubts and would it leave unclear wether they talked about being sure, while

Niemand bezweifelte, dass es gelingen würde.

would rather stress the point that nobody said he/she had doubts. (To use anzweifeln here you would need to transform the relative clause into an object: das Gelingen des Vorhabens, but that would result in a rather poor style.)

In cases where both anzweifeln and bezweifeln are a choice you would use anzweifeln if the doubts are rather weak or just starting to grow and bezweifeln if they are already profound and solid.

Answer 2

These words are indeed very closely related and can be used synonymously in most cases.

All of the above express that I doubt the correctness of this statement.

Ich zweifle an der Richtigkeit dieser Aussage.

Ich zweifle die Richtigkeit dieser Aussage an.

Ich bezweifle die Richtigkeit dieser Aussage.

There is no significant difference af meaning between the three that I'm aware of.

In some situations, one of them might be a bit more idiomatic than the others. The following examples might be from some newspaper article:

Der Abgeordnete zweifelte (offen) die Führungsqualitäten des Parteichefs an.

This basically implies that the representative (openly/publicly) attacked the party head by expressing doubts about his ability to lead. You wouldn't use bezweifeln to express that. You could, however, also use Zweifel as a noun:

Der Abgeordnete äußerte Zweifel an den Führungsqualitäten des Parteichefs.

… which has the same meaning, but might sound a bit less aggressive.

Der Abgeordnete zweifelt an den Führungsqualitäten des Parteichefs.

… would not necessarily require that he actually said anything. This could just be an assumption on the part of a commentator, based on other statements/observations.

Bezweifeln is more often used in direct speech:

Ich bezweifle (nicht), dass er das wirklich ernst meint.

In spoken language

Ich bezweifle das.

is more common than

Ich zweifle daran.

…, although both versions mean the same, i.e. "I doubt it/that".

Answer 3

Firstly, there are differences in grammar. "Anzweifeln" and "bezweifeln" can both take a direct object, while "zweifeln" connects with an object using the preposition "an" (which is likely where "anzweifeln comes from :)

Ich zweifele an etwas.

vs.

Ich zweifele etwas an.
Ich bezweifele etwas.

As far as meaning goes, I'd say that "anzweifeln" is the weakest doubting. The an-prefix gives it a bit of the notion of starting to doubt, though that's not always the intended meaning. "Zweifeln" is a bit stronger and "bezweifeln" is pretty solid doubting work.