Haltu í höndina mína þegar við förum út.

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Breakdown of Haltu í höndina mína þegar við förum út.

• fara: to go
• þegar: when
• út: out

Questions & Answers about Haltu í höndina mína þegar við förum út.

Why is it Haltu and not Hald or Halda?

Haltu is the singular imperative (command) form of the verb að halda (to hold). Icelandic imperatives often have special forms, and halda happens to form its imperative as haltu.

• Haltu! = (You) hold!
  The subject þú (you, singular) is usually omitted in commands, just like English often drops you.

Who is being addressed—one person or more than one?

This sentence addresses one person (informal singular you), because haltu is singular.
If you were speaking to more than one person, you’d use the plural imperative:

• Haldið í höndina mína þegar við förum út. = Hold my hand (all of you) when we go out.

What does halda í mean here, and why is there an í?

Að halda í is a very common Icelandic verb + preposition combination meaning to hold onto / hold (someone’s hand). The í is simply part of how the verb is used in this meaning; it’s not the “location/movement” í in the usual sense.
So:

• halda í X = hold (onto) X

Why is it í höndina (accusative with -ina) and not something like í höndinni?