Þú mátt velja hvaða borð sem er; öll borðin eru laus.

Mátt is the 2nd person singular form of the verb mega.

In this sentence, Þú mátt... means you may... / you are allowed to.... It usually expresses permission, though in some contexts mega can also suggest possibility.

So:

• mega = to be allowed to, may, can
• þú mátt = you may / you can

This is a very common verb, but its forms are a bit irregular, so learners often need time to get used to it.

In Icelandic, modal verbs like mega are followed directly by the infinitive of the main verb, without a separate word meaning to.

So:

• Þú mátt velja = you may choose

Here:

• mátt = may / are allowed to
• velja = choose

This works much like English modal verbs:

• you may choose
• not you may to choose

Other Icelandic modal-type verbs behave similarly.

Hvaða borð sem er means whichever table or any table.

This pattern is very common in Icelandic:

• hvaða + noun + sem er

It gives a meaning like it does not matter which one.

So:

• hvaða borð = which table
• hvaða borð sem er = whichever table / any table at all

This construction is useful to learn as a chunk, because it appears often in everyday Icelandic.

Yes, er is the present tense of vera (to be), but in the expression hvaða ... sem er, the whole phrase acts as a fixed idiomatic pattern.

Literally, it may look like something like which table that is, but that is not how you should understand it in normal English. The natural meaning is:

• any table
• whichever table

So it is best to learn hvaða ... sem er as a set expression rather than trying to translate each word too mechanically.

The verb velja normally takes a direct object, and direct objects are often in the accusative case.

Here, the noun is borð (table), which is a neuter noun. In the singular, the nominative and accusative forms of many neuter nouns are the same.

So:

• nominative singular: borð
• accusative singular: borð

That means you do not see a visible change here, even though the grammar still matters.

Öll borðin means all the tables.

Here is how it breaks down:

• öll = all (agreeing with a neuter plural noun)
• borðin = the tables

The noun borð is neuter, and in the plural definite form it becomes borðin.

The word öll has to agree with the noun in gender, number, and case, so because borðin is neuter plural, the adjective/quantifier is öll.

Because Icelandic adjectives and similar words agree with the noun they describe.

The noun borð is neuter, and here it is plural, so the correct form is öll.

Compare:

• allir = masculine plural
• allar = feminine plural
• öll = neuter plural

Since borð is a neuter noun, öll borðin is the correct combination.

Borðin is the definite nominative/accusative plural form of borð.

A quick breakdown:

• borð = table / tables (indefinite, depending on context)
• borðin = the tables

The ending -in here marks the definite plural for this neuter noun.

Also, because neuter plural nominative and accusative forms are often identical, borðin can serve in either role depending on the sentence.

Here laus means free, available, or unoccupied.

So borðin eru laus means the tables are free/available, for example in a restaurant or café.

This word can have slightly different meanings in other contexts, such as loose or not tied up, but here the natural sense is available.

The adjective has to agree with borðin.

Since borðin is neuter plural, the correct predicate adjective form is laus.

This may look surprising at first, because in Icelandic the neuter plural form of many adjectives is often the same as the basic dictionary form.

So:

• masculine plural: lausir
• feminine plural: lausar
• neuter plural: laus

That is why we get öll borðin eru laus.

This is a normal straightforward Icelandic clause:

• öll borðin = subject
• eru = are
• laus = free/available

So the structure is essentially:

• subject + verb + complement

That is very natural in Icelandic main clauses when nothing special is being emphasized.

The semicolon separates two closely related statements:

• Þú mátt velja hvaða borð sem er
• öll borðin eru laus

The second part explains or supports the first: you may choose any table, because all the tables are available.

In everyday writing, many people might also use a comma or simply split this into two sentences. The semicolon just links them a little more tightly.

Yes, in some contexts Icelandic can use other ways to express a similar idea, but hvaða borð sem er is a very natural and common choice.

It emphasizes that any one of the tables is fine. That is often the most idiomatic way to say it when you want to leave the choice completely open.

So even if there are alternative phrasings, this is a very useful pattern to learn and reuse.

Yes, several very useful pieces:

• Þú mátt... = you may / you are allowed to...
• velja = choose
• hvaða ... sem er = any ... / whichever ...
• öll + definite plural noun = all the ...
• eru laus = are free / available

If you remember those chunks, you can build many similar sentences, for example with other nouns:

• Þú mátt velja hvaða bók sem er.
• Þú mátt velja hvaða sæti sem er.

That makes this sentence a very good model for everyday Icelandic.