The Icelandic Verb System: Overview

Before you conjugate a single verb, it helps to see the whole terrain. The Icelandic verb has fewer moving parts than a Romance verb in one respect and more in another: there are only two simple tenses, but verbs inflect for person and number, there are two moods you must both master, there is a whole middle voice marked by -st, and the big compound notions (perfect, future) are built from smaller pieces rather than being tenses of their own. This page sketches that map; the detail pages fill it in.

Verbs agree with their subject

Unlike English (where only the third-person singular adds -s) and unlike its Scandinavian cousins (where verbs lost agreement entirely), Icelandic verbs inflect for person and number. The present-tense endings of a regular verb fall into a pattern of effectively four distinct endings across the six persons, because some plural forms share a shape. Take tala ("speak"):

The schematic ending pattern is -∅/-r/-r/-um/-ið/-a (where the "1sg" form often ends in the stem vowel -a or has no extra suffix). The 2nd and 3rd singular share -r; the 3rd plural matches the bare stem. So you are really tracking four shapes, not six.

Notice tala → tölum: the stem vowel a shifts to ö in the "we" form. This is u-umlaut, triggered by the -u- of the ending, and it is pervasive — meet it now, because it surfaces in noun and adjective endings too.

The central divide: weak vs strong

Every Icelandic verb is either weak or strong, and the distinction is defined by how it forms its preterite (simple past). This is the single most important classification in the verb system.

Weak verbs add a dental suffix — a -ð-, -d-, or -t- before the personal ending. The stem vowel stays put. Kalla ("call") → kallaði ("called").

Strong verbs form the preterite by changing the stem vowel — an inherited pattern called ablaut — with no dental suffix at all. Taka ("take") → tók ("took"). This is exactly the mechanism behind English sing/sang/sung and take/took; the two languages preserve the same ancient system.

Principal parts: four for strong verbs

To conjugate a strong verb fully you need its four principal parts: the infinitive, the past singular, the past plural, and the supine (the form used after hafa in the perfect). They are necessary because a strong verb can change its vowel more than once — once between present and past, and again between past singular and past plural.

For drekka you can see all four vowels at work: e → a → u → u. Weak verbs are simpler — their parts are predictable from the dental pattern, so they need fewer to be memorised. The strong-verb page organises the patterns into manageable classes.

Two simple tenses — and the rest is built

Icelandic has only two synthetic (one-word) tenses: the present and the preterite. Everything else English or Romance expresses with a dedicated tense, Icelandic builds periphrastically (with helper words) or leaves to context:

• Perfect ("have done") = hafa
  • supine: ég hef talað ("I have spoken").
• Future ("will do") = munu
  • infinitive, or — far more commonly — just the present tense plus context: ég kem á morgun ("I'm coming / I'll come tomorrow").

So there is no progressive tense, no future tense, and no separate perfect tense as such — fewer forms to drill than in Spanish or French, with the heavy lifting done by a couple of auxiliaries and by the present tense's wide reach (its own page).

Two moods: indicative and the living subjunctive

English speakers are tempted to file the subjunctive under "rare and bookish." In Icelandic that instinct is wrong: the subjunctive (viðtengingarháttur) is everyday. It appears in reported speech, after many conjunctions, in wishes and polite requests, in conditions, and after verbs of saying and thinking. You will hear it within minutes of any real conversation.

Do not treat the subjunctive as optional polish. It is a parallel set of endings you will master alongside the indicative, and pretending it is rare will leave you unable to understand ordinary sentences.

The middle voice: -st

Icelandic has a third voice (alongside active and passive) marked by a suffix -st on the verb. Historically it comes from a fused reflexive (sik → -st), and it does several jobs: genuine reflexive/reciprocal meaning, a passive-like sense, and — very often — a distinct lexical meaning of its own.

The takeaway for now: when you see -st glued to a verb, it is not a typo or an ending of the ordinary paradigm — it is the middle voice, and it often shifts the meaning, so it gets its own treatment.

Common Mistakes

The single present form does the work of English "speak" and "am speaking." Inventing an -andi progressive for every ongoing action is the classic English error.

There is no future tense to chase. The present plus a time word handles the near future.

After hafa you need the supine, the fourth principal part — tekið, not the finite past tók. Mixing them up is the commonest perfect-tense slip.

The subjunctive is not optional here; treating it as rare produces ungrammatical reported speech.

Key Takeaways

• Verbs agree with the subject; the present pattern is -∅/-r/-r/-um/-ið/-a, and watch the u-umlaut in the "we" form (tala → tölum).
• Every verb is weak (dental suffix in the past: kallaði) or strong (vowel change: tók). Classify by the past tense.
• Strong verbs need four principal parts (infinitive / past sg. / past pl. / supine).
• Only two simple tenses exist; perfect and future are built (hafa
  • supine; present-for-future).
• The subjunctive is everyday, not rare — master it alongside the indicative.
• The middle voice -st is a third voice that often changes a verb's meaning.