Sölubásinn er nálægt söluborðinu.

They break down like this:

• sölubásinn = the sales booth / the stall
• er = is
• nálægt = near / close to
• söluborðinu = the sales table / the sales counter

So grammatically, it is:

• subject: sölubásinn
• verb: er
• location phrase: nálægt söluborðinu

Sölu- is a very common compound element in Icelandic. It comes from sala meaning sale, and in compounds it works a lot like English sales-.

So:

• sölubás = sales booth / booth for selling
• söluborð = sales table / table or counter for selling

This kind of compounding is extremely common in Icelandic.

The ending -inn is the suffixed definite article, meaning the.

So:

• sölubás = a sales booth
• sölubásinn = the sales booth

Icelandic usually adds the to the end of the noun instead of putting a separate word in front, unlike English.

Here bás is a masculine noun, and -inn is the definite nominative singular ending in this form.

Because nálægt takes the dative case.

The basic noun is:

• söluborð = sales table / counter

Its forms here are:

• söluborðið = the sales table in the nominative/accusative
• söluborðinu = the sales table in the dative

Since nálægt governs the dative, you get:

• nálægt söluborðinu = near the sales table

So the ending is not random; it shows the grammatical role after nálægt.

When nálægt is followed by a noun phrase, yes, you should treat it as taking the dative.

Examples:

• nálægt húsinu = near the house
• nálægt skólanum = near the school
• nálægt mér = near me

So in your sentence, söluborðinu is in the dative because of nálægt.

• bás is masculine
• borð is neuter

That matters because gender affects:

• the form of the definite article
• case endings
• adjectives that might agree with the noun

So:

• sölubásinn has a masculine definite ending
• söluborðinu has a neuter dative definite ending

Learning the gender of each noun is important in Icelandic because it influences a lot of other grammar.

This is the normal straightforward order:

• subject
  • verb
    • complement/location phrase

So:

• Sölubásinn = subject
• er = verb
• nálægt söluborðinu = where it is

This is very similar to English The booth is near the table.

You can also move the location phrase for emphasis, for example:

• Nálægt söluborðinu er sölubásinn.

That is possible, but the original sentence is the most neutral and natural basic order.

Yes, but the meaning changes.

Compare:

• Sölubásinn er nálægt söluborðinu. = The sales booth is near the sales table.
• Sölubás er nálægt söluborði. = A sales booth is near a sales table.

You can also mix definite and indefinite depending on context:

• Sölubásinn er nálægt söluborði. = The sales booth is near a sales table.
• Sölubás er nálægt söluborðinu. = A sales booth is near the sales table.

So the endings are doing important meaning work.

They are related but not the same thing.

• sölubás usually means a booth, stall, or small selling space
• söluborð usually means a sales table or counter

So a sölubás is more like the whole selling setup or stall, while a söluborð is specifically the table/counter used for selling.

A few useful points:

• ö in sölu- is not English o. It is a rounded vowel, similar to German ö.
• á in nálægt sounds like ow in now.
• ð in borðinu is like th in this.
• The ending in nálægt has a rough consonant sound; many learners hear something like -laykht or -lighkht.

A rough learner-friendly approximation might be:

SÖ-lu-bow-sin er NOW-laykht SÖ-lu-bor-thi-nu

That is only approximate, but it helps you notice the main sounds.

Because vera = to be, and er is the normal neutral choice for saying where something is.

So Sölubásinn er nálægt söluborðinu is perfectly natural for simple location.

You could sometimes use a more specific verb such as stendur if you want to emphasize physical position:

• Sölubásinn stendur nálægt söluborðinu.

That feels more like The booth stands/is standing near the sales table.

But for a basic location statement, er is the safest and most common choice.

Yes — three things:

1. The definite article is attached to the noun

   • sölubásinn
   • söluborðinu

2. Nálægt takes the dative

   • so you must learn to expect forms like söluborðinu, húsinu, mér

3. Icelandic uses compounds very freely

   • sölu-
     • noun is a very common pattern

If you remember those three points, this sentence becomes much easier to understand and reuse.