The Infinitive, the Stem, and að

When you look up an Icelandic verb in a dictionary, you find its infinitive — the unconjugated citation form, like tala ("speak") or fara ("go"). The infinitive is your starting point for everything: it is the form the dictionary lists, the form you build the stem from, and the form that follows the little word að ("to"). This page covers three connected things — what the infinitive looks like, how to cut a verb's stem out of it, and when að does and does not appear before it. Actual conjugation (attaching person-number endings) lives on its own pages; here we are upstream of that, getting the raw materials right.

What an infinitive looks like

Almost every Icelandic infinitive ends in -a:

That final -a is the signature of the infinitive. A short, closed list of very common verbs instead ends in a stressed long vowel — these are contracted monosyllables where an older ending wore away, leaving the bare root vowel:

These end in -á (or -ó) rather than -a. They are worth flagging precisely because they break the "infinitive ends in -a" expectation, and they happen to be high-frequency. But they are the exception; the overwhelming default is -a.

Finding the stem

The stem is what you attach person-number endings to, and you get it by removing the final -a from the infinitive:

• tala → stem tal- → ég tala, þú talar…
• kalla → stem kall- → ég kalla, þú kallar…
• lesa → stem les- → ég les, þú lest…

The stem is the "naked" verb. Every ending — present, past, the lot — clamps onto it. Getting the cut right matters: if you mis-slice tala as ta- you will build broken forms. The safe procedure is mechanical: chop the last -a, keep everything else. For the -á/-ó monosyllables there is essentially nothing to chop — the verb is already at root size (fá, sjá), which is part of why they conjugate irregularly. The conjugation pages handle their forms; just know the stem-cutting rule is for the ordinary -a infinitives.

að: the infinitive marker

The word að is Icelandic's "to" — the marker that flags an infinitive, exactly like English "to" in "I want to go." It is spelled with an eth (ð) and no accent: að, never áð or ad. Do not confuse it with að the conjunction ("that"), which is the same word doing a different job — that one introduces a whole clause with its own conjugated verb.

The everyday pattern is verb + að + infinitive, where the second verb names what you intend, promise, hope, or try to do:

Here að behaves just like English "to," and an English speaker has little trouble: "I promise to come" = ég lofa *að koma*. The trap is the next section.

The big split: modals take a BARE infinitive

Here is the rule that catches almost every English speaker. A small set of modal verbs governs the infinitive directly, with no að. After a modal, the second verb is a bare infinitive:

The core modals that drop að are vilja (want), geta (can/be able), mega (may/be allowed), skulu (shall), and munu (will — formal). With these, inserting að is wrong: ég vil fara, never ég vil að fara. English misleads you here, because English "want" does take "to" ("I want to go"), so the natural instinct is to translate it as að — and that instinct produces the single most common early error in Icelandic infinitive syntax.

Why the split? Modals are not really expressing a separate action you "want to do"; they fuse with the main verb into one predicate of ability, permission, or volition. The bare infinitive signals that tight fusion. Non-modals like ætla, lofa, reyna, vonast keep their own meaning and link to the infinitive more loosely — hence að. The clean way to hold it: the five fusion-modals (vilja, geta, mega, skulu, munu) drop að; ordinary verbs keep it.

A practical wrinkle worth honesty: eiga ("ought to / be supposed to") and a couple of others behave like modals semantically but actually take að (ég á að fara, "I'm supposed to go"). So the bare-infinitive club is specifically vilja, geta, mega, skulu, munu; do not over-generalise the rule to every modal-ish verb. The modals page draws the full boundary.

Common Mistakes

English "want to" tempts you to insert að. After vilja (and geta, mega, skulu, munu) the infinitive stands bare.

Geta governs a bare infinitive (here the supine talað). No að.

The mirror error: dropping að after an ordinary verb. Lofa, ætla, reyna, vona all keep að.

Að is written with eth (ð) and carries no accent — not ad, not áð.

Key Takeaways

• The infinitive is the citation form; it almost always ends in -a (tala, fara, lesa), with a few high-frequency monosyllables in -á/-ó (fá, ná, sjá, slá, róa).
• The stem is the infinitive minus -a (tala → tal-); every conjugational ending attaches to it.
• að ("to") marks the infinitive after ordinary verbs (ég ætla að fara, ég lofa að koma) and is spelled with eth, no accent.
• Modals drop að — after vilja, geta, mega, skulu, munu the infinitive is bare (ég vil fara, ég get talað). This is the mirror image of English "want to" and the top early error.
• Eiga and a few modal-like verbs do keep að, so the bare-infinitive list is specifically those five.