Hvar sem við hittumst, tölum við smá íslensku saman.

Hvar means where. When Icelandic adds sem after a question word, it often creates an -ever / no matter ... meaning.

So:

• hvar = where
• hvar sem = wherever / no matter where

So Hvar sem við hittumst means wherever we meet or no matter where we meet.

A useful pattern is:

• hver sem = whoever
• hvað sem = whatever
• hvar sem = wherever

Here við is the pronoun we.

You can tell because it is the subject of the verbs:

• við hittumst = we meet
• við tölum = we speak

The preposition við would normally be followed by a noun or pronoun object, not used as the subject of a verb.

Because the verb here is að hittast, not just að hitta.

• að hitta einhvern = to meet someone / see someone
• að hittast = to meet each other

The -st ending is very common in Icelandic and often gives a middle/reflexive/reciprocal meaning. In this sentence, við hittumst means we meet each other.

Compare:

• Við hittum Jón. = We meet Jón.
• Við hittumst. = We meet each other.

This is because Icelandic follows a verb-second pattern in main clauses.

The normal standalone sentence is:

• Við tölum smá íslensku saman.

But when another element comes first — here the clause Hvar sem við hittumst — the finite verb of the main clause comes before the subject:

• Hvar sem við hittumst, tölum við smá íslensku saman.

So the inversion is normal and grammatical.

Because íslensku is the form used here as the object of tölum.

The language name is:

• íslenska in the nominative
• íslensku in the accusative

Since tala takes the language as its object, Icelandic uses the accusative here:

• tala íslensku = speak Icelandic

The word smá means a little / some / a bit of here. In modern Icelandic it is very often used as an indeclinable word, so it stays smá instead of changing its ending.

It is accusative singular.

That is the usual case for the direct object after að tala when you name the language being spoken:

• tala ensku
• tala dönsku
• tala íslensku

So in this sentence, íslensku is the direct object of tölum.

Saman means together.

It adds the idea that the speakers are using Icelandic with each other, as a shared activity.

Without it, the sentence would still be grammatical:

• Hvar sem við hittumst, tölum við smá íslensku.

But saman makes it sound more explicitly mutual and natural in context: we speak a little Icelandic together.

It most naturally describes a habit or repeated situation.

The present tense in Icelandic is often used for things that regularly happen:

• Hvar sem við hittumst, tölum við smá íslensku saman.

This suggests something like whenever / wherever we meet, this is what we do.

So it is not mainly about one single meeting, but about a repeated pattern.

Yes, and that would shift the emphasis.

• Hvar sem við hittumst = wherever we meet → focuses on place
• Alltaf þegar við hittumst = whenever we meet → focuses on time/repetition

So the original sentence emphasizes no matter where the meeting happens.
Your alternative emphasizes every time the meeting happens.

Both can be natural, but they are not exactly the same.

Because the first part is a subordinate clause placed before the main clause:

• Hvar sem við hittumst = subordinate clause
• tölum við smá íslensku saman = main clause

In standard Icelandic writing, it is normal to separate that fronted clause from the main clause with a comma.