Á sumrin förum við oft á litla hátíð í borginni.

Á sumrin means in the summer or during the summer months.

A learner often notices two things here:

• á can mean many things, but in time expressions it often means in/during
• sumrin is plural, even though English often uses singular: in the summer

This is a very common Icelandic way to talk about a recurring season in a general sense. So:

• Á sumrin = in summer / during the summers / every summer season

It sounds natural in Icelandic, even if the English translation is usually singular.

Because Icelandic often uses the plural definite form when talking about seasons in a general, habitual way.

So:

• á sumrin = in summer / during the summer
• literally, it looks like in the summers

This does not usually mean several separate summers in a strongly literal English sense. It is just the normal Icelandic idiom for talking about what happens in summertime in general.

Compare the idea:

• Á sumrin förum við oft... = In summer, we often go...

This is because of the Icelandic verb-second rule, often called V2.

In a main clause, the finite verb usually comes in the second position. If something other than the subject comes first, the verb still stays second, and the subject comes after it.

So here:

• Á sumrin = first element
• förum = second element, so it must come here
• við = subject, so it comes after the verb

That gives:

• Á sumrin förum við oft...

If the sentence started with the subject instead, you would get:

• Við förum oft á litla hátíð í borginni á sumrin.

Both are grammatical, but the original puts extra emphasis on in summer.

Förum is the 1st person plural present tense form of fara, which means to go.

So:

• ég fer = I go
• við förum = we go

In this sentence, förum means we go.

This is an irregular vowel change that happens in the verb fara.

Its present-tense forms are not built with exactly the same vowel all the way through:

• ég fer
• þú ferð
• hann/hún/það fer
• við förum
• þið farið
• þeir/þær/þau fara

So förum is just the correct present plural form. This is something learners usually need to memorize as part of the verb’s conjugation.

Oft means often, and its position is natural in Icelandic.

Because the sentence begins with Á sumrin, the verb has to come second:

• Á sumrin
  • förum

Then the subject comes:

• við

Then the adverb:

• oft

So the structure is:

• Á sumrin | förum | við | oft | ...

If the sentence began with the subject instead, you would also naturally get:

• Við förum oft...

So the placement of oft is normal and closely connected to Icelandic word order.

Because Icelandic commonly uses fara á for going to an event or attending something.

So:

• fara á hátíð = go to a festival
• fara á tónleika = go to a concert
• fara á fund = go to a meeting

This is a very common pattern. Even though á often literally means on, here it is just the normal preposition used with events.

So á litla hátíð means to a small festival.

Because hátíð is a feminine singular noun, and after á in this expression it is in the accusative.

The adjective has to match the noun in:

• gender
• number
• case

So:

• noun: hátíð = feminine singular
• case here: accusative
• adjective form needed: litla

That is why Icelandic says:

• á litla hátíð

not, for example:

• á lítill hátíð
• á lítilli hátíð

Those would not fit the grammar here.

Because í means in, and here it describes location: the festival is in the city.

With í, Icelandic usually distinguishes between:

• accusative for motion into something
• dative for being in a place

Here the meaning is location, not movement into the city, so Icelandic uses the dative:

• í borginni = in the city

Also, borginni includes the definite article, so it means:

• borginni = the city

They do different jobs:

• Á sumrin = in/during the summer
• á litla hátíð = to a small festival
• í borginni = in the city

So even though English may use in or to, Icelandic uses different prepositions depending on the expression.

A useful way to think about it is:

• á is used here for a time expression and for going to an event
• í is used here for being inside/in a place

This is why both prepositions appear in the same sentence.

Because litla hátíð is indefinite, while borginni is definite.

So:

• á litla hátíð = to a small festival
• í borginni = in the city

In Icelandic, the definite article is usually added to the end of the noun rather than written as a separate word. That is why:

• borg = city
• borgin = the city
• borginni = in the city / to the city’s dative form with the article

So the sentence is talking about:

• some small festival
• the city already known or understood from context

Yes. A very natural alternative is:

• Við förum oft á litla hátíð í borginni á sumrin.

That still means the same basic thing. The difference is mainly emphasis and flow.

• Á sumrin förum við oft... puts in the summer first, so it feels more topical or emphasized
• Við förum oft... á sumrin starts more neutrally with we

Both are good Icelandic. The original sentence is especially useful for showing the verb-second pattern.