Ég efa það.

• Ég = I
• efa = doubt
• það = it / that

So grammatically, this is a very straightforward subject + verb + object sentence.

Because efa is the present tense, first-person singular form of the verb að efa = to doubt.

So:

• að efa = to doubt (infinitive)
• ég efa = I doubt

Even though English sometimes changes the verb form very little, Icelandic has its own conjugation patterns, and this is simply the correct form used with ég here.

It can be either, depending on context.

In Icelandic, það is used for both:

• it
• that

In a short sentence like Ég efa það, English usually translates it as I doubt it, but the Icelandic word itself can also correspond to that in other contexts.

Here, það is the direct object of efa, so it is in the accusative.

A useful thing to know is that for this pronoun, the nominative and accusative forms are the same in the neuter singular:

• nominative: það
• accusative: það

So even though the form does not change, its role in the sentence does: here it is the object.

A rough English-friendly pronunciation would be:

yeg EH-va thahth

A few important details:

• é in Ég is pronounced roughly like ye
• þ is like th in thin
• ð is like th in this, though at the end of a word it can sound very soft

So:

• Ég ≈ yeg
• efa ≈ EH-va
• það ≈ thahth / thað with a soft final sound

Both can mean I doubt it, but they are built differently.

• Ég efa það uses the verb efa directly with an object
• Ég efast um það uses efast plus the preposition um

So the grammar is:

• efa + object
• efast um + object

A learner will often meet both patterns. This sentence uses the simpler direct-object structure.

Normally, you should include ég.

Unlike languages that often drop subject pronouns, Icelandic usually keeps them. So:

• Ég efa það = normal
• Efa það = generally incomplete on its own

So yes, the ég is important here.

Yes. This is the normal, neutral word order:

• Ég = subject
• efa = verb
• það = object

So it follows a basic SVO pattern: Subject – Verb – Object.

More broadly, Icelandic is often described as a verb-second language, but in a simple sentence where the subject comes first, the result looks very similar to ordinary English word order.

Usually, yes. Að efa often suggests real doubt or skepticism, not just mild uncertainty.

So Ég efa það can sound a bit firmer than:

• I’m not sure
• Maybe not

It is more like:

• I doubt it
• I’m skeptical about that

The exact strength depends on tone and context, but it generally expresses genuine doubt.