Ég mæli með þessum veitingastað, því þjónustan þar er bæði hröð og vinaleg.

Að mæla með is a fixed expression meaning to recommend or to speak in favor of.

So:

• Ég mæli með ... = I recommend ...

Even though mæla by itself can have other meanings in other contexts, in this sentence mæla með should be learned as one phrase.

Also, mæli is the 1st person singular present tense form, so it matches ég:

• ég mæli = I recommend

Because the phrase mæla með takes the thing recommended in the dative case.

So the noun has to change form:

• dictionary form: veitingastaður = restaurant
• dative singular: veitingastað

And the demonstrative changes too:

• þessi = this
• þessum = dative singular form

So:

• með þessum veitingastað = with this restaurant grammatically
• but idiomatically: recommend this restaurant

This is a very common Icelandic pattern: the case is controlled by the verb phrase or preposition.

In Icelandic, the definite article is usually attached to the end of the noun instead of appearing as a separate word.

So:

• þjónusta = service
• þjónustan = the service

That is why you see þjónustan as one word.

In this sentence, þjónustan is the subject of the second clause:

• þjónustan þar er ... = the service there is ...

Because þessi already makes the noun definite enough in many contexts.

So:

• þessi / þessum veitingastað = this restaurant

Very often, Icelandic uses:

• demonstrative + noun without also adding the suffixed definite article.

You can sometimes hear or see forms like þessum veitingastaðnum, but that usually sounds more emphatic, more specific, or more colloquial depending on context. In a neutral sentence like this one, þessum veitingastað is perfectly natural.

Here því means because or since.

So the sentence structure is:

• Ég mæli með þessum veitingastað = first clause
• því þjónustan þar er bæði hröð og vinaleg = reason clause

So því introduces the reason.

A useful note: því can also be a form of a pronoun in other contexts, but here it is a conjunction meaning because. Context tells you which meaning is intended.

In everyday speech, learners will also often hear:

• af því að = because

Þar means there, but here it is best understood as at that place / at that restaurant.

So:

• þjónustan þar = the service there
• more naturally in English: the service at that restaurant

Icelandic often uses þar to refer back to a place that has just been mentioned. English may sometimes leave this unstated, but Icelandic often says it explicitly.

Because Icelandic adjectives must agree with the noun they describe in gender, number, and case.

The noun here is:

• þjónustan
• singular
• feminine
• nominative

So the adjectives must also be feminine singular nominative:

• hröð = fast
• vinaleg = friendly

This is true even though they come after er and function as predicate adjectives:

• þjónustan er hröð
• þjónustan er vinaleg

English adjectives do not change form this way, but Icelandic adjectives do.

Bæði ... og ... means both ... and ...

It is used to link two things together. Here it links two adjectives:

• bæði hröð og vinaleg = both fast and friendly

This pattern is very common in Icelandic and can connect not only adjectives, but also nouns, verbs, or whole clauses.

Examples:

• bæði kaffi og te = both coffee and tea
• bæði skemmtilegur og fróðlegur = both fun and informative

Because the sentence contains two clauses:

1. Ég mæli með þessum veitingastað
2. þjónustan þar er bæði hröð og vinaleg

The comma separates these clauses, and því introduces the reason for the first clause.

Icelandic punctuation often uses commas to mark clause boundaries clearly, so this comma is natural and standard.

Not especially; it is fairly straightforward.

The second clause is:

• þjónustan þar er bæði hröð og vinaleg

You can think of it as:

• þjónustan = subject
• þar = adverbial element, referring to the restaurant
• er = verb
• bæði hröð og vinaleg = complement

What may feel unusual to an English speaker is that þar appears inside the noun phrase area of the clause, but semantically it just means there / at that place. The overall order is natural Icelandic.

These two letters are very important in Icelandic:

• þ is pronounced like th in thing
• ð is pronounced roughly like th in this

In this sentence:

• þessum
• því
• þjónustan

all begin with þ, so use the thing sound.

And:

• hröð

ends with ð, which is usually softer and lighter than an English th at the end of a word.

So a good learner rule is:

• þ = unvoiced th
• ð = voiced th

That will get you very close.