Learn Hardcore Icelandic: Ég sef mikið á frídögum.

Icelandic verbs change form depending on the subject, and 1st person singular (I) often has a different ending from 2nd / 3rd person singular.

For sofa:

1st person singular: ég sef
2nd/3rd person singular: þú sefur / hann sefur

So sefur is correct for “you/he/she/it sleeps”, but with ég, the correct form is sef.

What exactly does mikið mean here? Is it “a lot” or “much”?

In this sentence, mikið functions like an adverb meaning “a lot”:

Ég sef mikið – I sleep a lot.

Grammatically, mikið is the neuter singular of the adjective mikill (much, many, great), but after many verbs it behaves adverbially:

Hann talar mikið – He talks a lot.
Við vinnum mikið – We work a lot.

So you can think of sef mikið as “sleep a lot”.

Is mikið an adjective or an adverb here?

Formally, mikið is the neuter singular form of the adjective mikill, but in this context it’s used adverbially, modifying the verb sef (“sleep”).

There is no noun like “sleep” being described (you’re not saying “a big sleep”); instead, you are describing how much you sleep. That’s an adverbial role, even though the form looks adjectival.

Can I change the word order and say Ég mikið sef á frídögum or Mikið sef ég á frídögum?

Ég mikið sef á frídögum – sounds wrong/unidiomatic in normal speech.
Mikið sef ég á frídögum – is grammatically possible, but has strong emphasis on mikið (“A lot I sleep on days off”), and would sound poetic or rhetorical.

Neutral, everyday word order is:

Ég sef mikið á frídögum.

A very natural alternative, still normal:

Á frídögum sef ég mikið. – On days off, I sleep a lot. (emphasis on the time phrase)

Why is it á frídögum and not í frídögum for “on days off”?

For time expressions meaning “on [a day / days]”, Icelandic normally uses á + dative:

á mánudögum – on Mondays
á kvöldin – in the evenings
á jólunum – at Christmas

So á frídögum = on days off / on holidays (days off from work/school).

The preposition í is used in other time meanings, e.g.:

í fríinu – during the vacation / in the holiday period (a specific vacation)

Why is it frídögum and not something like frídagar?

Frídögum is the dative plural of frídagur (day off, holiday).

Key forms of frídagur (masculine):

Nominative singular: frídagur – a day off
Dative singular: frídegi – on a day off
Nominative plural: frídagar – days off
Dative plural: frídögum – on days off

After á in these regular, recurring time expressions, Icelandic uses the dative plural:

á mánudögum – on Mondays
á frídögum – on days off

So á frídögum literally: on (the) days off.

Why is there no word for “my” in á frídögum, even though the English is “on my days off”?

Icelandic often omits possessive pronouns (my, your, his, etc.) when it’s already clear whose thing it is from context or from the subject.

Ég sef mikið á frídögum.

Literally: I sleep a lot on days off.
Naturally understood as: I sleep a lot on *my days off.*

You’d only add a possessive if you needed contrast or emphasis:

Ég sef mikið á mínum frídögum, ekki þínum.
I sleep a lot on *my days off, not yours.*

What is the difference between á frídögum and í fríinu?

á frídögum – on days off in general; a repeated/habitual situation.
- “On my days off (whenever I have them), I sleep a lot.”
í fríinu – in the vacation / during the holiday; typically one specific period of time.
- Ég sef mikið í fríinu. – I sleep a lot during the vacation.

So á frídögum is about individual days off as a recurring pattern, while í fríinu is about a particular holiday period.

Why is the present tense sef used for a habitual action? In English we also say “I sleep” here, but how does this work in Icelandic?

In Icelandic, the simple present tense is used both for:

Current/general truths or states
- Ég er þreyttur. – I am tired.
Habitual or repeated actions
- Ég sef mikið á frídögum. – I sleep a lot on days off.
- Ég fer í sund á morgnana. – I go swimming in the mornings.

So Ég sef mikið á frídögum is clearly understood as a habit, not as something happening right now. Icelandic doesn’t need a separate “I am sleeping” form here to show that difference; context does the job.

Can I drop the pronoun and just say Sef mikið á frídögum?

Normally, no.

Unlike Spanish or Italian, Icelandic usually requires the subject pronoun, especially with verbs like sofa:

Ég sef mikið á frídögum. – normal
Sef mikið á frídögum. – feels incomplete/odd in standard language

You might see the pronoun dropped in commands (not here, since this isn’t an imperative), or in some informal, clipped styles, but as a learner you should keep the pronoun: Ég sef…

Where can I put the time phrase á frídögum in the sentence?

All of these are grammatically correct, but with slightly different emphasis or style:

Ég sef mikið á frídögum.
- Neutral; focus on the sleeping; time is added information.
Á frídögum sef ég mikið.
- Emphasis on on days off (that’s when this happens).
Ég sef á frídögum mikið.
- Possible, but sounds a bit awkward or marked. Less natural than 1 or 2.

The most typical everyday versions are 1 and 2, with 1 probably the most common neutral choice.

How do you pronounce Ég sef mikið á frídögum?

Approximate pronunciation (using English-like hints):

Ég – often like “yai” with a soft throaty sound at the end: [jɛiːɣ]
sef – like “sehv”, with a long e: [sɛːv]
mikið – “MEE-kith” or “MEE-kith/MI-kith”, final ð is a soft “th” (as in this), often very weak: [ˈmiːcɪð]
á – like “ow” in cow: [auː]
frídögum – roughly “FREE-tho-gum”: [ˈfriːˌðœːɣʏm]
- frí – free with a long í: [friː]
- dö – like “duh” but with rounded lips: [dœː]
- gum – “gum” with a short, central vowel: [ɣʏm]; the g here is a soft fricative, not a hard English g.

Spoken smoothly, the whole sentence will sound something like:
[jɛiːɣ sɛːv ˈmiːcɪð auː ˈfriːˌðœːɣʏm].