Learn Hardcore Icelandic: Á markaðnum sel ég gömul föt til að spara peninga. - At the market I sell old clothes to save money.

Icelandic main clauses are verb-second (V2). When you front something (here, the place phrase Á markaðnum), the finite verb must be the second element, so the subject (ég) follows the verb:

Neutral: Ég sel gömul föt ...
With fronting: Á markaðnum sel ég gömul föt ... Both are correct; the fronted version emphasizes the location.

What case is markaðnum, and why is it used here?

It’s dative singular definite. The preposition á takes:

Dative for location: á markaðnum (at/in the market)
Accusative for motion towards: á markaðinn (to the market) This sentence describes location, so dative is required.

Why is definiteness on markaðnum expressed with a suffix instead of a separate word for “the”?

Icelandic has no separate definite article. Definiteness is marked by a suffix attached to the noun (and it affects adjective endings too). Here:

Indefinite: á markaði (at a market)
Definite: á markaðnum (at the market)

Why markaðnum and not markaðinum?

For many masculine nouns ending in -aður, the expected dative-definite ending -inum is reduced after ð, giving -ðnum. So you normally see markaðnum.

Why is it sel and not selja?

Sel is the 1st person singular present of the verb selja (to sell). Icelandic verbs conjugate:

Present (key forms): ég sel, þú selur, við seljum, þið seljið, þau selja
Past: ég seldi
Past participle: selt

Do I capitalize ég like English “I”?

No. Ég is only capitalized at the beginning of a sentence, like any other word. Icelandic does not capitalize the first-person pronoun by default.

Why is the adjective gömul used with föt?

Gömul is the neuter plural (nom/acc) form of the adjective gamall (old). Föt is neuter plural, so the adjective must agree in gender and number: gömul föt.

Is föt always plural? Can I say a single “cloth/garment” with fat?

Föt means clothes and is plural-only in this sense. The singular fat exists but means a vat/tub in modern Icelandic. To refer to a single garment, use flík or a specific item, e.g., bolur (T‑shirt), jakki (jacket).

Why isn’t it gömlum fötum?

Because gömul föt is a direct object and thus in accusative plural. For neuter nouns, nominative and accusative forms are identical, and the adjective’s strong accusative plural neuter is gömul (not gömlum, which is dative plural).

What does til að do here? Could I just use að?

Til að introduces a purpose clause (in order to + infinitive). You generally need til for this meaning. So:

Purpose: til að spara peninga (in order to save money) You may also see the slightly more explicit til þess að in careful style.

Does til always take the genitive?

With a noun, yes: til Reykjavíkur, til vinanna. But in til að + infinitive, til is part of the fixed purpose expression and does not assign a case (there’s no noun to inflect).

Why spara and not something like bjarga for “save”?

spara = save (money/time/resources), economize
bjarga = save/rescue (a person, a situation)
vista = save (a computer file) So spara peninga is the correct choice here.

Why is peninga plural? Could it be singular pening?

Icelandic often uses the plural peningar/peninga for uncountable “money.” Singular peningur is a coin or a sum. You will also hear colloquial spara pening (singular as a mass noun), but spara peninga is very standard.

Could I say í markaðnum instead of á markaðnum?

Not here. With places like markets, schools, concerts, etc., Icelandic typically uses á (on/at). Í (in) is for being inside something enclosed, and í markaðnum would sound odd in this meaning.

How would I say “to the market” instead of “at the market”?

Use accusative after á for motion:

Direction: á markaðinn (to the market)
Location: á markaðnum (at/in the market)

How would I say “the old clothes” or “my old clothes”?

With definiteness, the adjective takes weak endings and the noun adds the definite suffix:

The old clothes: gömlu fötin
My old clothes: gömlu fötin mín Indefinite stays strong: gömul föt.

Any quick pronunciation tips for tricky letters here?

á ≈ ow in English “cow.”
ö in gömul/föt ≈ French eu in “peur.”
ð in að/markaðnum is a voiced th (as in “this”); in -aðn-, it’s often soft and blends into the n.
Stress is on the first syllable of each word: Á-MAR-kað-num, SEL, ÉG, GÖ-mul, FÖT, TIL, AÐ, SPA-ra, PE-nin-ga.