Við fórum hlæjandi heim eftir kvöldmatinn, því samtalið var svo gott.

Hlæjandi is the present participle of að hlæja (to laugh). In this sentence, it means something like laughing or while laughing.

So:

• að hlæja = to laugh
• hlæjandi = laughing

In Við fórum hlæjandi heim, the participle works almost like an adverb and describes how they went home: they went home laughing.

It is very similar to English expressions like:

• We went home laughing
• We walked away smiling

Fórum is the 1st person plural past tense of að fara (to go).

The verb að fara is irregular, so its past forms have to be learned:

• ég fór = I went
• þú fórst = you went
• hann/hún/það fór = he/she/it went
• við fórum = we went
• þið fóruð = you went
• þeir/þær/þau fóru = they went

So Við fórum simply means we went.

The form forum without the accent is not correct in Icelandic. The accented ó matters.

In Icelandic, heim is a very common adverb meaning homeward / home in the sense of motion toward home.

So:

• fara heim = go home
• koma heim = come home

This is very much like English, where we say go home, not usually go to home.

Compare:

• Við fórum heim = We went home
• Við vorum heima = We were at home

This is an important distinction:

• heim = motion toward home
• heima = location at home

Yes, Við fórum heim hlæjandi is also possible.

Both versions are understandable:

• Við fórum hlæjandi heim
• Við fórum heim hlæjandi

The difference is mostly one of style, rhythm, and emphasis, not basic meaning.

• hlæjandi heim can feel a bit more tightly connected, as if laughing colors the whole movement home.
• heim hlæjandi can feel like the fact of going home is stated first, with hlæjandi added afterward.

Icelandic word order is fairly flexible, especially with adverb-like elements such as participles.

Eftir kvöldmatinn means after dinner or more literally after the evening meal.

Breakdown:

• eftir = after
• kvöldmatur = dinner / evening meal
• kvöldmatinn = the dinner in the accusative singular

Here, eftir takes the accusative when it means after in time. That is why you get kvöldmatinn, not just kvöldmatur.

So:

• nominative: kvöldmaturinn = the dinner
• accusative: kvöldmatinn = the dinner

Many learners notice that the ending changes with case, and this is a good example of that.

Both can exist, but they are not exactly the same in feel.

• eftir kvöldmat = after dinner, more general
• eftir kvöldmatinn = after the dinner / after that dinner, more specific

In actual usage, Icelandic often uses the definite form where English would simply say after dinner. So eftir kvöldmatinn can still sound very natural even if English would not usually say after the dinner.

So the definite article here does not necessarily sound overly specific in the way it might in English.

Excellent question. Því can indeed be a pronoun form in other contexts, but here it is a conjunction meaning because or for.

In this sentence:

• því samtalið var svo gott = because the conversation was so good

So here því introduces the reason.

This use is common in written and spoken Icelandic. It is not the pronoun here.

You may also see af því að for because, which is often very transparent for learners:

• ... af því að samtalið var svo gott = ... because the conversation was so good

Because því here introduces a subordinate clause, and Icelandic often does not keep the main-clause verb-second pattern after such conjunctions.

Main clause:

• Samtalið var svo gott.
• subject first, verb second

After því:

• því samtalið var svo gott

This is normal subordinate-clause order: conjunction + subject + verb.

So the sentence structure is:

• Við fórum hlæjandi heim eftir kvöldmatinn = main clause
• því samtalið var svo gott = subordinate clause giving the reason

Samtalið means the conversation.

Breakdown:

• samtal = conversation
• samtalið = the conversation

The ending -ið is the definite article attached to a neuter singular noun.

Icelandic usually adds the definite article to the end of the noun instead of using a separate word like English the.

So:

• samtal = a conversation / conversation
• samtalið = the conversation

Because the adjective has to agree with the noun samtalið.

• samtal is neuter
• samtalið is singular
• therefore the adjective must also be neuter singular

That gives:

• góður = masculine singular
• góð = feminine singular
• gott = neuter singular

Since samtalið is neuter, you get:

• samtalið var svo gott = the conversation was so good

Here svo means so, in the sense of so good.

• var svo gott = was so good

Depending on context, English might translate this as:

• was so good
• was very good
• was such a good conversation

But the most direct meaning is so.

In Icelandic, svo is a very common word with several uses, including:

• so
• then
• thus / like that

In this sentence, it clearly intensifies gott.

Samtal usually means conversation or discussion in a fairly neutral sense.

Related words:

• samtal = conversation, discussion
• spjall = chat, casual talk
• ræða can mean speech, and as a verb að ræða means to discuss

So in this sentence, samtalið suggests the conversation as a shared exchange, not necessarily something very formal, but a bit more neutral than spjall.

If you changed it to spjallið, the tone might become slightly more casual: the chat rather than the conversation.

A fairly literal breakdown would be:

• Við = we
• fórum = went
• hlæjandi = laughing
• heim = home
• eftir kvöldmatinn = after the dinner / after dinner
• því = because
• samtalið = the conversation
• var = was
• svo gott = so good

So a literal version is:

We went laughing home after the dinner, because the conversation was so good.

Natural English would usually smooth that into something like:

We went home laughing after dinner, because the conversation was so good.

It sounds natural and idiomatic.

Several things in it are very normal Icelandic:

• fara heim = go home
• using a participle like hlæjandi = laughing
• eftir kvöldmatinn = after dinner
• því to introduce a reason
• adjective agreement in samtalið var svo gott

A native speaker might choose slightly different wording depending on style, but the sentence itself is perfectly good Icelandic.