Learn Hardcore Icelandic: Ég set fótinn á stólinn þegar ég er ekki að hlaupa lengur. - I put my foot on the chair when I am not running anymore.

So ég set corresponds to I put / I am putting in English. You only use setja after another verb (e.g. mig langar að setja…, ég vil setja…) or as a dictionary form.

Why is it fótinn and not just fótur?

Two things are happening in fótinn:

It’s definite:
- fótur = a foot
- fótinn = the foot
Icelandic usually attaches the definite article as an ending: -inn, -an, -ið, etc., rather than using a separate word like English the.
It’s in the accusative case (see next question).
The noun fótur (foot) declines like this in the singular (main forms):
- Nominative (subject): fótur – the foot (as subject): fóturinn
- Accusative (direct object): fót – the foot (object): fótinn
- Dative: fæti – the foot: fætinum
- Genitive: fótar – the foot’s: fótsins

In your sentence, fótinn is “the foot” as an object, so you get the accusative form with the definite ending: fót-inn.

Why is fótinn in the accusative case?

Fótinn is the direct object of the verb set:

Ég set fótinn … = I put the foot …

In Icelandic, the direct object of a “normal” action verb like setja is typically in the accusative. So:

Ég set stólinn – I (am) put(ting) the chair. → stólinn accusative
Ég set fótinn á stólinn – I (am) put(ting) the foot on the chair. → fótinn accusative

So the verb setja “governs” an accusative object: you put something (that something goes in accusative).

Why is it á stólinn and not á stólnum?

The preposition á (“on, onto”) can take either accusative or dative, and the case changes the meaning:

á
- accusative → movement / direction (“onto, to a position on”)
á
- dative → location (“on, resting on”)

Compare:

Ég set fótinn á stólinn.
→ I put my foot onto the chair (movement to a new place).
stólinn is accusative.
Fóturinn er á stólnum.
→ The foot is on the chair (no movement, just location).
stólnum is dative.

Because the sentence describes putting (a change of position), you must use á with the accusative: á stólinn.

Why is it stólinn (“the chair”) and not just stól (“a chair”)?

Icelandic generally uses the definite article (ending -inn here) when you have a specific, known thing in mind:

stóll = a chair
stólinn = the chair

In a realistic context, if you say you put your foot on a chair, you probably mean a particular chair that is present in the situation, so Icelandic often prefers the definite form.

Grammatically, stólinn is:

the noun stóll (chair)
in the accusative singular (because of movement with á)
with the definite ending -inn → stól-inn

Could I say Ég set fót á stól instead of Ég set fótinn á stólinn?

You can, grammatically, but it will sound less natural or more “bare” in most real situations.

Differences:

Ég set fót á stól.
- fót (foot) and stól (chair) are indefinite (no “the”).
- This can sound a bit like “I place a foot on a chair”, as if they are new, non‑specific items.
Ég set fótinn á stólinn.
- fótinn = the foot (naturally understood as my foot).
- stólinn = the chair (some specific chair in the context).
- This is what people normally say.

So Ég set fótinn á stólinn is the idiomatic way to talk about your own foot going onto a specific chair that’s in the situation.

What’s the difference between ég hleyp and ég er að hlaupa?

Both involve the verb hlaupa (to run), but they’re used slightly differently:

ég hleyp
Literally: “I run.”
- Can mean a general habit: “I (usually) run.”
- Can describe a present action, but without strongly highlighting the ongoing process.
ég er að hlaupa
Literally: “I am to run / at running.”
- This construction (vera + að + infinitive) often corresponds to English be + -ing.
- Emphasizes that the action is ongoing right now: “I am running.”

In your sentence, þegar ég er ekki að hlaupa lengur highlights the ongoing activity that has stopped: when I am no longer in the process of running.

Why is ekki placed before að hlaupa, and can I move it?

The basic word order of the “progressive” construction is:

vera + ekki + að + infinitive

So:

ég er að hlaupa – I am running
ég er ekki að hlaupa – I am not running

Here ekki (not) normally goes right after the conjugated verb (er) and before the að + infinitive.

You wouldn’t normally say:

✗ ég er að ekki hlaupa
✗ ég er að hlaupa ekki lengur (this sounds wrong/weird)

In your sentence, the order is:

… þegar ég er ekki að hlaupa lengur.

er – am
ekki – not
að hlaupa – running
lengur – anymore / any longer (time)

This is the standard and natural order.

What exactly does lengur mean here, and how is it different from lengra?

Lengur and lengra are related but used differently:

lengur
- Refers to time: any longer, anymore.
- Used with negation to say an action has stopped:
  - Ég er ekki lengur hér. – I am not here anymore.
  - Hann býr ekki lengur í Reykjavík. – He no longer lives in Reykjavík.
lengra
- Refers to distance (comparative of langt = far): farther/further in space.
- Example:
  - Ég get ekki farið lengra. – I can’t go any farther.

In your sentence, lengur fits because you’re talking about time — when I am not running any longer, i.e., when I have stopped the activity.

Could I say þegar ég hætti að hlaupa instead of þegar ég er ekki að hlaupa lengur?

Yes, and it’s quite natural, but there is a nuance:

þegar ég er ekki að hlaupa lengur
- Literally: “when I am not running anymore.”
- Focuses on the state after the activity has ceased (the time when you’re no longer in the process).
þegar ég hætti að hlaupa
- Literally: “when I stop running.”
- Focuses more on the moment of stopping.

So:

If you mean “at the time after I’ve finished running”, þegar ég er ekki að hlaupa lengur matches well.
If you mean “the moment I stop running”, þegar ég hætti að hlaupa is a little sharper and more action‑focused.

Both are grammatical; choice depends on the nuance you want.

How do you pronounce Ég set fótinn á stólinn þegar ég er ekki að hlaupa lengur?

A rough, learner‑friendly approximation (not strict IPA):

Ég ≈ “yeh” (like English yeah but shorter; in some accents closer to “yei”)
set ≈ “set” (like English set, but with a slightly tenser e)
fótinn ≈ “FOH-tin”
- ó like “oh”
- tt is often pronounced with a little puff of air /ht/, but you can think “FOH-tin”
á ≈ “ow” (as in cow)
stólinn ≈ “STOH-lin”
þegar ≈ “THEH-yar” (the þ like English th in thin)
ég again ≈ “yeh”
er ≈ “air”
ekki ≈ “EH-kki” (the kk is a hard, aspirated k sound)
að ≈ “ath” (the ð like soft th in this, but often very light)
hlaupa ≈ “HLOI-pa”
- hl is like hl with a breathy h
- au sounds roughly like oi in oil
lengur ≈ “LENG-ur” (like English leng-er, but the r is tapped/rolled)

You don’t need perfect Icelandic phonetics to be understood; getting the vowels roughly right and remembering that þ and ð are “th”-type sounds will already help a lot.