Localize Is

Translate to Icelandic (is) — High-Fidelity Skill

Scope & Variants

Icelandic is a single standard target — Modern Icelandic (íslenska). There are no significant regional dialects, no diglossia. The Icelandic Language Committee (Íslensk málnefnd) actively coordinates national standardization.

| Locale | Notes | |--------|-------| | is / is-IS | Standard Icelandic (Iceland). Default and only target. |

Practical reality: Icelandic translation has one target. The defining quality concern is extreme language purism — Iceland actively coins native Icelandic words for new technological concepts and aggressively rejects loanwords. This is not a stylistic preference; it is national policy supported by both the government's Language Committee and a strong cultural consensus among speakers.

Icelandic is a conservative North Germanic language

Icelandic is the closest modern descendant of Old Norse. It retains:

• The full 4-case system (Nom/Acc/Dat/Gen) that other Scandinavian languages mostly lost.
• Three genders with strong/weak adjective declension.
• Verb conjugation by person (unlike Swedish/Norwegian/Danish where verbs have one form for all persons).
• Suffixed definite articles that decline by case (hesturinn → hestinn → hestinum → hestsins).
• Letters lost in most modern Latin-script languages: ð (eth) and þ (thorn).

This means Icelandic translation requires substantially more grammatical precision than Norwegian/Swedish/Danish.

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Register Auto-Detection (Apply Before Translating)

Modern Icelandic uses þú universally — the formal þér is archaic and used only in ceremonial/legal contexts (less than 1% of usage). Even Iceland's president is addressed as þú.

Auto-detect from source:

| Source signal | Target register | |---------------|-----------------| | Casual / conversational / personal | Casual þú — direct verbs, short sentences. Possessive þinn / þín / þitt (lowercase). | | Neutral product UI / docs (DEFAULT) | Neutral þú — þú throughout, imperative buttons, present-tense status. | | Legal / banking / government | Formal þú — still þú (NEVER þér in modern UI), but use full constructions, prefer impersonal passives, careful native vocabulary. |

Hard rule: NEVER use þér in modern Icelandic UI. Even banking and government use þú.

Hard rule: source register matching for vocabulary — Icelandic has both common-register and literary-register vocabulary. Match the source — don't elevate a casual English stay to a literary Icelandic equivalent.

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Critical Hard Rules (Severity ≥ 2.0 — Auto-Fail If Wrong)

1. EXTREME language purism — anglicisms strongly rejected (severity 2.5)

Icelandic is the most purist major European language for IT terminology. The Icelandic Language Committee has coined native Icelandic words for every common tech concept, and these are the expected and required terms in Icelandic UI:

| English | ✓ Icelandic native (REQUIRED) | ✗ Anglicism / loanword (REJECTED) | |---------|-------------------------------|-----------------------------------| | computer | tölva ("number-prophetess" — Halldór Halldórsson's 1965 coinage) | kompjúter, computer | | telephone | sími (from Old Norse "thread") | telefón | | television | sjónvarp (literally "sight-throw") | televísjón, TV | | email | tölvupóstur ("computer-mail") | email, emaila | | software | hugbúnaður ("mind-equipment") | software | | hardware | vélbúnaður ("machine-equipment") | hardware | | browser | vafri ("wanderer") | browser | | website | vefsíða ("web-page") OR vefur | website | | internet | internetið OR veraldarvefurinn ("world-wide-web") | (internet acceptable) | | keyboard | lyklaborð ("keys-board") | keyboard | | mouse | mús (native word reused) | mouse | | screen | skjár | screen | | password | lykilorð ("key-word") | password | | file | skrá | file | | folder | mappa (from "map") | folder | | user | notandi | user | | settings | stillingar | settings | | dashboard | yfirlit ("overview") | dashboard | | account | reikningur | account | | video | myndband ("picture-band") | video | | photo | mynd | foto | | download (v.) | hlaða niður ("load down") | downloada | | upload (v.) | hlaða upp ("load up") | uploada | | click (v.) | smella | klikka | | save (v.) | vista | seiva | | delete (v.) | eyða | deleta | | update (v.) | uppfæra | updatea | | log in | skrá sig inn | logga, logga inn | | log out | skrá sig út | logga út | | select (v.) | velja | selekta | | cancel (v.) | hætta við ("stop with") | kansella | | search (v.) | leita | sörtsa | | share (v.) | deila | sjera |

Hard rule: ALL "verb-with-Icelandic-suffix-on-English-root" forms are rejected by Icelandic users. klikka, deleta, seiva, updatea, uploada, downloada, sörtsa, sjera, logga — all WRONG. Use the native verb.

A small set of established loanwords IS accepted:

• app (also forrit) — both used
• internet (alongside internetið)
• wifi (also þráðlaust net)
• cookie (in tech contexts; vafrakaka is the formal term)
• Brand names: Google, Microsoft, Apple, GitHub — stay as-is.

But for the COMMON verbs and nouns above, native Icelandic is required.

2. ð (eth) and þ (thorn) preservation (severity 2.5)

Icelandic uses two letters that no other major modern language uses:

• ð (eth, voiced /ð/ as in English "this") — appears in middle/end of words. NEVER replace with d.
• þ (thorn, unvoiced /θ/ as in English "thin") — appears at start of words. NEVER replace with th.

| ✗ Stripped to ASCII | ✓ Correct | |---------------------|-----------| | madur | maður (man) | | tholinmaedi | þolinmæði (patience) | | islenska | íslenska (Icelandic) | | thessi | þessi (this) | | hladu nidur | hlaða niður (download — ð in hlaða) | | sidan | síðan (the page) | | theta er | þetta er (this is) | | vidmot | viðmót (interface) |

Note: ð never appears at start of a word (Old Norse phonotactic constraint). Word-initial þ ONLY. Mid/end words can have ð.

3. æ and ö preservation (severity 2.0)

In addition to ð and þ, Icelandic uses æ (the æ ligature, /ai/ sound) and ö (umlauted o, /œ/ sound):

| ✗ Stripped | ✓ Correct | |------------|-----------| | baeta | bæta | | haetta | hætta | | broker → broker | (loanword keeps brokering) | | forrit / kerfid | (no æ/ö in this example, just illustrating) | | sjonvarp | sjónvarp | | toluvert | töluvert |

Other diacritics: á é í ó ú ý (acute-marked long vowels). All essential.

4. Word integrity — compound words written as one (severity 2.0)

Icelandic forms compound words by concatenation. Splitting them changes meaning or produces nonsense.

| ✗ Wrong (split) | ✓ Correct (joined) | English | |-----------------|---------------------|---------| | gagna grunnur | gagnagrunnur | database | | notanda viðmót | notandaviðmót | user interface | | lykil orð | lykilorð | password | | tölvu póstur | tölvupóstur | email | | hug búnaður | hugbúnaður | software | | vef síða | vefsíða | website | | lykla borð | lyklaborð | keyboard |

Compound gender rule: the gender of an Icelandic compound is the gender of the LAST element. gagnagrunnur is masculine (because grunnur = base is masculine), tölvupóstur is masculine, notandaviðmót is neuter (because viðmót is neuter).

5. Four-case system (severity 2.5)

Icelandic retains all 4 cases from Old Norse. Cases are: nefnifall (Nom), þolfall (Acc), þágufall (Dat), eignarfall (Gen).

| Case | Question | Use | Example (m. "hestur" — horse) | Example (f. "skrá") | |------|----------|-----|-------------------------------|---------------------| | Nom | hver? hvað? | Subject | hestur | skrá | | Acc | um hvern? hvað? | Direct object | hest | skrá | | Dat | frá hverjum? hverju? | Indirect object, with many preps | hesti | skrá | | Gen | til hvers? hvers? | Possession, with some preps | hests | skrár |

Definite forms add the suffixed article and continue to decline:

• Indef.: hestur — hest — hesti — hests
• Def.: hesturinn — hestinn — hestinum — hestsins

(That's 8 forms for one noun across 2 numbers × 4 cases × 2 (def/indef) = 16 forms total per noun. Icelandic is very inflected.)

6. Preposition-governed case (severity 2.5)

Each preposition governs a specific case. Wrong case = critical error.

Accusative (Acc) prepositions:

• um (about, around): um kerfið
• gegnum (through): gegnum vafrann
• kringum (around): —

Dative (Dat) prepositions (most common):

• frá (from): frá notandanum (dat. of "notandinn")
• með (with): með kerfinu (NOT með kerfið)
• af (off, from): af síðunni
• úr (out of): úr möppunni
• að (to/at): að notandanum

Genitive (Gen) prepositions:

• til (to): til þess (NOT til það)
• vegna (because of): vegna villu
• milli (between): milli skrár og möppu

Two-case prepositions (Acc vs Dat by motion):

• í (in / into):
• Motion INTO → ACC: í kerfið (into the system)
• Location IN → DAT: í kerfinu (in the system)
• á (on / onto):
• Motion ONTO → ACC: á skjáinn (onto the screen)
• Location ON → DAT: á skjánum (on the screen)

Critical UI errors to avoid:

| ✗ Wrong | ✓ Correct | Reason | |---------|-----------|--------| | með það kerfi | með því kerfi | dat. after með | | frá það | frá því | dat. after frá | | til það | til þess | gen. after til | | í kerfinu (motion sense) | í kerfið | acc. for motion INTO | | í kerfið (location sense) | í kerfinu | dat. for location IN |

7. Definite article suffixes that decline (severity 2.0)

Icelandic has no separate definite article word (unlike English "the"). Instead, the definite article is suffixed to the noun AND it declines by case.

| Gender | Indef. Nom | Def. Nom | Def. Acc | Def. Dat | Def. Gen | |--------|------------|----------|----------|----------|----------| | Masc. (hestur — horse) | hestur | hesturinn | hestinn | hestinum | hestsins | | Fem. (kona — woman) | kona | konan | konuna | konunni | konunnar | | Neut. (barn — child) | barn | barnið | barnið | barninu | barnsins |

| ✗ Wrong | ✓ Correct | |---------|-----------| | hesturinn (in accusative) | hestinn | | barnið (in dative) | barninu | | konan (in genitive) | konunnar |

This is uniquely difficult among Western European languages — the article suffix isn't just a marker, it inflects.

8. Adjective declension — strong vs weak (severity 2.0)

Icelandic adjectives have two declension classes:

• Strong (indefinite, predicative): used when noun is indefinite or adj. is predicative.
• nýtt kerfi (a new system) — strong neuter indef.
• kerfið er nýtt (the system is new) — strong predicative.
• Weak (definite, with article): used when noun is definite.
• nýja kerfið (the new system) — weak.

Wrong choice = critical error:

| ✗ Wrong | ✓ Correct | Why | |---------|-----------|-----| | stór vandamálið | stóra vandamálið | def. noun needs weak adj | | nýtt kerfið | nýja kerfið | def. needs weak | | nýja kerfi | nýtt kerfi | indef. needs strong | | góður dagurinn | góði dagurinn | def. weak |

9. Verb conjugation by person (severity 2.0)

UNLIKE Swedish/Norwegian/Danish (where verbs have ONE form for all persons), Icelandic verbs conjugate by person and number.

Example: vista (to save)

| Person | Form (present) | Form (past) | |--------|----------------|-------------| | ég (I) | vista | vistaði | | þú (you sg.) | vistar | vistaðir | | hann/hún/það (he/she/it) | vistar | vistaði | | við (we) | vistum | vistuðum | | þið (you pl.) | vistið | vistuðuð | | þeir/þær/þau (they) | vista | vistuðu |

UI critical: ég vista ✓ (NOT ég vistar); þú vistar ✓ (NOT þú vista); þið vistið ✓.

10. V2 word order (severity 2.0)

Like other Scandinavian languages, Icelandic is strict V2 — finite verb in position 2 of declarative main clauses.

| ✗ Wrong | ✓ Correct | |---------|-----------| | Í dag notandinn vistar skrána | Í dag vistar notandinn skrána | | Núna kerfið hleður gögn | Núna hleður kerfið gögn | | Þegar þú smellir, þú sérð... | Þegar þú smellir, sérðu... (V2 after subordinate clause) |

11. Three-gender system (severity 2.0)

| Gender | Endings | Example | Article suffixes | |--------|---------|---------|------------------| | Masculine (karlkyn) | typically -ur, -i, -ir | hestur, vafri | -inn | | Feminine (kvenkyn) | typically -a, -ur (some), consonant | skrá, mappa, kona, brú | -in | | Neuter (hvorugkyn) | typically -a (some), -i (some), consonant | barn, kerfi, hús, viðmót | -ið |

| ✗ Wrong | ✓ Correct | Reason | |---------|-----------|--------| | sú kerfi | það kerfi | kerfi = neuter | | það vafri | sá vafri | vafri = masc. | | hinn skrá | hin skrá | skrá = fem. |

12. Past participle agreement (severity 2.0)

Past participles agree with subject in gender + number:

| Subject | Participle (e.g., "vistaður" — saved) | |---------|----------------------------------------| | m. sg. (hesturinn) | vistaður (hesturinn er vistaður) | | f. sg. (skráin) | vistuð (skráin er vistuð) | | n. sg. (kerfið) | vistað (kerfið er vistað) | | m. pl. (hestarnir) | vistaðir | | f. pl. (skrárnar) | vistaðar | | n. pl. (kerfin) | vistuð |

Skráin er vistað ✗ → Skráin er vistuð ✓.

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Pronouns and Possessives

Personal pronouns (decline by case!)

| English | Nom | Acc | Dat | Gen | |---------|-----|-----|-----|-----| | I | ég | mig | mér | mín | | you (sg.) | þú | þig | þér | þín | | he | hann | hann | honum | hans | | she | hún | hana | henni | hennar | | it (m.) | hann | hann | honum | hans | | it (f.) | hún | hana | henni | hennar | | it (n.) | það | það | því | þess | | we | við | okkur | okkur | okkar | | you (pl.) | þið | ykkur | ykkur | ykkar | | they (m.) | þeir | þá | þeim | þeirra | | they (f.) | þær | þær | þeim | þeirra | | they (n.) | þau | þau | þeim | þeirra |

Critical: pronouns decline. með þú ✗ → með þér ✓ (dat. after með).

Possessive pronouns

| English | m. | f. | n. | |---------|-----|-----|-----| | my | minn | mín | mitt | | your sg. | þinn | þín | þitt | | his | hans (invariable) | hans | hans | | her | hennar (invariable) | hennar | hennar | | our | okkar (invariable, or okkar declined) | okkar | okkar | | your pl. | ykkar | ykkar | ykkar | | their | þeirra | þeirra | þeirra | | reflexive (own) | sinn | sín | sitt |

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UI Conventions

Buttons — imperative (concise)

| English | ✓ Icelandic | |---------|-------------| | Save | Vista | | Cancel | Hætta við (NOT Kansella) | | Delete | Eyða | | Send | Senda | | Edit | Breyta | | Search | Leita | | Confirm | Staðfesta | | Continue | Halda áfram | | Submit | Senda inn | | Sign in / Log in | Skrá sig inn | | Sign out | Skrá sig út | | Sign up | Skrá sig / Búa til reikning | | Next | Næsta / Áfram | | Back | Til baka | | Done | Lokið / Búið | | OK | OK / Í lagi | | Close | Loka | | Upload | Hlaða upp | | Download | Hlaða niður | | Refresh | Uppfæra | | Settings | Stillingar | | Apply | Beita | | Reset | Endurstilla | | Select all | Velja allt | | Add more | Bæta við |

Status messages — present tense + ellipsis

| English | ✓ Icelandic | |---------|-------------| | Loading… | Hleður… (3rd person sg present) | | Saving… | Vistar… | | Sending… | Sendir… | | Processing… | Vinnur úr… / Vinnur… | | Connecting… | Tengir… | | Searching… | Leitar… | | Translating… | Þýðir… | | Please wait | Vinsamlegast bíddu / Bíddu aðeins |

Completion messages — concise

| English | ✓ Icelandic | |---------|--------

…

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: i18n-agent
• Source: i18n-agent/i18nstack
• License: MIT
• Homepage: https://i18nagent.ai

Install and usage instructions live in the source repository linked above.