Við borðum kvöldmat heima, þó að veitingastaðurinn sé opinn.

In Icelandic it’s standard to separate a main clause and a following subordinate clause with a comma. Here you have:

• Main clause: Við borðum kvöldmat heima
• Subordinate concessive clause: þó að veitingastaðurinn sé opinn So the comma is normal and expected in writing.

þó að introduces a concessive subordinate clause (roughly although / even though). Common alternatives you’ll see:

• þótt (very common, often interchangeable with þó að)
• þrátt fyrir að (more like despite the fact that) Example swap:
• Við borðum kvöldmat heima, þótt veitingastaðurinn sé opinn.

After concessive expressions like þó að / þótt, Icelandic often uses the subjunctive in the subordinate clause.

• sé = present subjunctive of vera (to be)
• er = present indicative So … þó að veitingastaðurinn sé opinn is the typical/neutral choice. Using er can happen in some contexts, but the subjunctive is the standard you should learn.

borðum is present tense of borða (to eat), 1st person plural (we). Icelandic present tense can cover both:

• habitual: We eat dinner at home
• current/planned: We’re eating / We eat (today/tonight) at home If you specifically want the “in progress right now” feel, Icelandic often uses:
• Við erum að borða kvöldmat heima… (We are eating dinner at home…)

kvöldmatur is the dictionary form (nominative). As the direct object of borða, it goes into the accusative:

• nominative: kvöldmatur
• accusative: kvöldmat So borða + accusative → borðum kvöldmat.

heima is an adverb meaning at home / home. Icelandic often uses adverbs where English uses at + noun:

• heima = at home
• úti = outside
• inni = inside You can also express location with prepositions in other constructions, but heima is the most natural here.

The ending -inn is the definite article attached to the noun, meaning the:

• veitingastaður = a restaurant
• veitingastaðurinn = the restaurant Icelandic usually attaches the as a suffix, and adjectives around it follow special “definite” patterns in other contexts.

Adjectives agree with the noun in gender, number, and case.
veitingastaðurinn is:

• masculine
• singular
• nominative (it’s the subject of the clause)

So the adjective takes masculine singular nominative:

• opinn (masc. sg. nom.) Other forms (for comparison):
• opið (neut. sg. nom./acc.)
• opin (fem. sg. nom.)
• opnir / opnar / opin (plural, depending on gender)

In subordinate clauses introduced by þó að, Icelandic typically keeps a subject–verb order:

• … að veitingastaðurinn sé opinn Main clauses more often show V2 word order (finite verb in the second position), but subordinate clauses generally do not.

Key bits:

• Við: ð is often very soft (sometimes almost like a “th” in this, sometimes barely heard), so roughly Vith.
• þó: þ is like th in thing (voiceless).
• að: often pronounced like a very reduced ath/ah, with the ð weak.
• kvöldmat: ö is like a rounded vowel (similar to German ö); kvöld sounds roughly like kvöl(d) with the d often softened.
• veitingastaðurinn: stress is on the first syllable: VEI- (Icelandic stress is almost always initial).

In modern Icelandic, þó is commonly used as an adverb meaning though (often at the end of a clause), but as a clause introducer you normally use þó að or þótt.
So these are natural:

• Við borðum kvöldmat heima, þó að veitingastaðurinn sé opinn.
• Við borðum kvöldmat heima; veitingastaðurinn er samt opinn. (… the restaurant is still open.) Using þó alone to introduce the clause is less standard than þó að / þótt.