Ég vel það fyrsta.

I choose the first one.

Breakdown of Ég vel það fyrsta.

• ég: I
• velja: to choose
• það fyrsta: the first one

Questions & Answers about Ég vel það fyrsta.

Why is vel used here instead of velja?

Vel is the 1st person singular present tense form of the verb velja (to choose).

So:

• að velja = to choose
• ég vel = I choose
• þú velur = you choose
• hann/hún/það velur = he/she/it chooses

This is one of those Icelandic verbs where the present-tense form does not look exactly like the infinitive, so learners often have to memorize it.

What exactly does það fyrsta mean?

Here það fyrsta means the first one or that first one, depending on context.

Icelandic often uses a pronoun plus an adjective/ordinal to stand in for a whole noun phrase when the noun is understood.

So instead of saying a full noun like:

• Ég vel það fyrsta epli. = I choose that first apple.
  (not the most natural example, but it shows the structure)

you can simply say:

• Ég vel það fyrsta. = I choose the first one.

The noun is left out because it is already clear from context.

Why is there no separate word for one?

Because Icelandic usually does not need to say one in this kind of sentence.

English says:

• the first one

but Icelandic can just say:

• það fyrsta

The idea of one is understood automatically. This is very common when talking about options, items, choices, answers, and so on.