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.

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.

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 ✓.

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

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
Saved	Vistað / Vistuð (gender depends on subject)
Done	Lokið / Búið
Translation complete	Þýðingu lokið ("translation-DAT completed")
File uploaded	Skrá hlaðin upp ("file loaded up")
Sent	Sent
Payment successful	Greiðsla tókst / Greitt

Empty states — `Engar X` / `Ekkert X`

✗ Verbose	✓ Concise
Engar niðurstöður fundust	Engar niðurstöður
Þú hefur engin verkefni ennþá	Engin verkefni ennþá
Það er ekkert hér	Ekkert hér

Drag-and-drop

drag → draga (or imperative Dragðu)
drop → sleppa (or imperative Slepptu) — NOT losa (= release/loosen, wrong sense)
Combined: Dragðu skrár hingað (Drag files here) / Slepptu til að hlaða upp (Release to upload).

File picker — `Velja` (native action verb)

✓ Icelandic
Velja skrá (Choose a file)
Velja skrár (Choose files)
Smelltu til að velja (Click to choose)

Quantity expressions

✗ Calque	✓ Native
25+ tungumál	meira en 25 tungumál
+{count} til viðbótar	og {count} til viðbótar

Error messages — what + next step

✗ Bare	✓ With next step
Skrá fannst ekki.	Skrá fannst ekki. Athugaðu slóðina.
Netvilla.	Netvilla. Reyndu aftur.

Punctuation, Numbers, Dates, Currency

Punctuation

Mark	Icelandic	Notes
Question mark	`?`	Same as English
Comma	`,`	Different conjunction rules
Period	`.`	Same
Colon	`:`	Same
Quotation marks	`„…"` (gæsalappir — low-9 / high-9)	Same as German style
Apostrophe	only in foreign names

Comma rules

Rule	Example
NO comma before `og` (and)	Veldu skrá og smelltu.
NO comma before `eða` (or)	Veldu skrá eða möppu.
Comma before `að` (that, subordinating)	Ég sé, að skráin er opin.
Comma before `sem` (relative — non-restrictive)	Skráin, sem var vistuð…
Comma before `ef` (if)	Vistaðu, ef þú vilt.
Comma before `því` (because)	Hætt við, því það mistókst.
Comma before `vegna þess að` (because)	Hætt við, vegna þess að það mistókst.
Comma before `en` (but)	Hratt, en skilvirkt.

Numbers

Format	Pattern	Example
Thousands separator	period (.)	1.234.567
Decimal separator	comma (,)	3,14 / 99,99 (rare for ISK)
Negative	`-25`
Percent	`25 %` (with space)

Dates

Format	Example	Use
DD.MM.YYYY	15.01.2024	Default Icelandic format
D. mánuður YYYY	15. janúar 2024	Long-form prose
YYYY-MM-DD	2024-01-15	Technical/API only

Icelandic month names (lowercase):

#	Icelandic
1	janúar
2	febrúar
3	mars
4	apríl
5	maí
6	júní
7	júlí
8	ágúst
9	september
10	október
11	nóvember
12	desember

Weekdays (lowercase): mánudagur, þriðjudagur, miðvikudagur, fimmtudagur, föstudagur, laugardagur, sunnudagur.

Week starts Monday.

Time

24-hour preferred: 14:30 or kl. 14:30 (kl. = klukkan).

Currency — Icelandic króna (ISK / kr.) — NO DECIMALS

Format	Pattern	Example
Symbol after amount	`kr.` (with period)	9.999 kr.
ISO code	ISK	9.999 ISK

CRITICAL: Icelandic króna has NO decimal subdivisions (aurar were abolished in 2002). Always use whole numbers.

✗ 99,99 kr. (decimals)
✗ 99.99 kr. (English-style)
✓ 100 kr. (whole numbers)
✓ 1.234 kr. (period as thousands separator)
✓ 9.999 kr. (large amounts more common in Iceland — ISK has low purchasing power, ~140 ISK = 1 USD)

Iceland is NOT in the eurozone (not even an EU member — Iceland is EEA). Never use EUR for Icelandic localization.

Terminology — preferred Icelandic terms (PURIST)

English	✓ Icelandic (REQUIRED)	✗ Avoid (anglicism)
user	notandi	user
account	reikningur	akkáunt
password	lykilorð ("key-word")	password
settings	stillingar	settings
dashboard	yfirlit	dashboard
email	tölvupóstur	email, mejl
link	tengill	link
website	vefsíða	website
folder	mappa	folder
file	skrá	file
device	tæki	device
phone	sími	telefón
computer	tölva	kompjúter
application / app	forrit / app (accepted)	applikation
update (v.)	uppfæra	updatea
save	vista	seiva
delete	eyða	deleta
upload	hlaða upp	uploada
download	hlaða niður	downloada
sign in / log in	skrá sig inn	logga inn
sign up	skrá sig	—
search	leita	sörtsa
click	smella	klikka
share	deila	sjera
profile	prófíll (accepted loanword) / persónusíða	—
notifications	tilkynningar	—
privacy	persónuvernd ("person-protection")	privacy
terms	skilmálar	—
support	stuðningur	—
help	hjálp / aðstoð	—
feedback	endurgjöf	feedback
menu	valmynd ("choice-picture")	menu
home	heim / upphafssíða	home
browser	vafri	browser
screen	skjár	screen
keyboard	lyklaborð	keyboard
mouse	mús	mouse
software	hugbúnaður	software
hardware	vélbúnaður	hardware
video	myndband	video
photo	mynd / ljósmynd	foto
window	gluggi	—
menu bar	valmyndastika	—
search bar	leitarstika	—
icon	tákn	ikon
error	villa	error
warning	viðvörun	warning
language	tungumál ("tongue-thing")	—
font	letur / leturgerð	font
size	stærð	size
color	litur	color
build (software)	byggja / smíða	builda
deploy	dreifa / setja upp	deploya
pipeline (CI/CD)	pipeline (keep)	—
commit (git)	commit (keep)	—
merge (git)	sameina / merge (keep in code)	mergea
repository	vörusöfn (formal) / repository	—
sync	samstilla	—
API	API (keep — Latin always)	—
cache	skyndiminni / cache	—
log (n.)	annáll / skrá	—
URL	vefslóð ("web-trail")	—
WiFi	þráðlaust net ("wireless net") / WiFi	—

Tech identifiers — keep in Latin

Inside Icelandic text (Latin alphabet anyway), these stay as-is:

Git, GitHub, Docker, npm, pip
HTTP, REST, GraphQL, OAuth, JWT
JSON, XML, YAML, CSV, PDF
Brand names: Google, Microsoft, Apple, iPhone, Android
Commands, paths, URLs, code, placeholders

False Friends — Critical

Icelandic word	Actually means	NOT this	Correct for the English
gift	poison OR "married"	"gift" (present)	"gift" → gjöf
fart	speed / pace	(English meaning unrelated)	—
bjór	beer	(OK loanword)	—
fjall	mountain	—	—
`aktuelt` (if it appears)	current	"actual"	"actual" → raunverulegt
`eventuelt`	possibly	"eventually"	"eventually" → að lokum / á endanum
álit	opinion	"elite"	"elite" → úrvalslið
bók	book	(OK)	—

The gift = poison false friend is the classic Icelandic translation trap.

Calque / Anti-Pattern List

✗ Calque	✓ Native Icelandic	Reason
gerir skilning / Það gerir vit	er skynsamlegt / það meikar sens (colloquial only)	"Makes sense" calque
í lok dags	þegar allt kemur til alls	"At the end of the day" calque
Taka það á næsta stig	Fara lengra	"Take to next level" calque
Á sama blaðsíðu	Sammála / Á sama máli	"On the same page" calque
gera úrbætur	bæta	"Make improvements" — use verb
gefa svar	svara	"Provide an answer" — use verb
Fáðu þýðingu á nokkrum mínútum	Þýðing á nokkrum mínútum	"Get X done" structural calque
Haltu verkefnunum þínum samstilltum	Tryggðu samstillingu verkefna	"Keep X synced" calque
AI-knúið	byggt á AI / knúið af AI	"X-powered" calque
klikka	smella	Anglicism — use native verb
deleta	eyða	Anglicism
seiva	vista	Anglicism
uploada	hlaða upp	Anglicism
downloada	hlaða niður	Anglicism
updatea	uppfæra	Anglicism
kompjúter	tölva	Anglicism — use Iceland's national coinage
email	tölvupóstur	Anglicism — use native

Self-Check Checklist (Run Before Returning Output)

Language purism (auto-fail on miss)

Native Icelandic terms used for IT vocabulary: tölva, sími, vafri, tölvupóstur, hugbúnaður, lyklaborð, notandi, stillingar, skrá, mappa, lykilorð.
No anglicism-verb hybrids: no klikka, deleta, seiva, uploada, downloada, updatea, sörtsa, sjera.
No raw anglicism nouns: no kompjúter, email, password, dashboard, browser, software (unless explicitly part of a brand/product name).

Special characters (auto-fail)

ð (eth) present where required — never d. Examples: maður, viðmót, síðan, hlaða niður.
þ (thorn) present where required (word-initially) — never th. Examples: þetta, þú, þannig, þýðing.
æ present where required — never ae. Examples: bæta, hætta.
ö present where required — never o or oe. Examples: tölva, sjónvarp.
á é í ó ú ý acute-marked vowels preserved.

Accuracy

Compound words written as one word — no gagna grunnur, tölvu póstur.
Four-case system correct — preposition-governed case respected.
i / á two-case prepositions: ACC for motion, DAT for location.
Definite article suffix declines by case (hesturinn / hestinn / hestinum / hestsins).
Strong vs weak adjective correctly chosen (strong for indef./predicative, weak for def.).
Verb conjugation by person correct (ég vista, þú vistar, við vistum, þið vistið).
V2 word order in main clauses.
Past participle agreement with subject gender/number (skráin er vistuð).
Gender (m/f/n) correct on every article and adjective.
Pronoun case correct (pronouns decline! með þér, frá honum, til þess).
Compound gender = last element rule applied.
ICU plurals: standard one / other for Icelandic.
Placeholders preserved.
Numbers: comma decimal, period thousands.
Dates: DD.MM.YYYY.
Currency: ISK króna, NO decimals — 9.999 kr. not 99,99 kr..

Register

þú throughout — never þér (archaic).
Possessive matches: þinn / þín / þitt consistently.

UI conventions

Buttons use imperative (Vista, Eyða, Hætta við).
Status uses present + ellipsis (Hleður…, Vistar…).
Completion concise (Vistað, Þýðingu lokið).
Empty states concise (Engar niðurstöður).
Drag-drop uses Dragðu + Slepptu.
No comma before og / eða.
Error messages include next step.

Currency / Region

ISK (kr.) for Icelandic locale — NEVER EUR (Iceland is not in eurozone, not even EU).
No decimals on ISK — 100 kr., 1.234 kr., never 99,99 kr..

Worked Example — Standard is UI

Source (neutral product UI):

Welcome back! You have 3 new files in your account. Click Continue to review them or Cancel to stay here. Saving your changes…

Register check: neutral product UI → casual þú, present-tense status, native Icelandic vocabulary.

Translation:

Velkomin/n aftur! Þú ert með 3 nýjar skrár á reikningnum þínum. Smelltu á Halda áfram til að skoða þær eða Hætta við til að vera áfram hér. Vistar breytingarnar þínar…

Why this works:

Velkomin/n — adjective participle (fem./masc. with slash for gender-neutral; or use masc. Velkominn if gender-neutral plural isn't possible here).
Þú ert með — þú + 2nd-person sg. verb ert + með (with). Idiomatic Icelandic for "you have".
3 nýjar skrár — nýjar f. pl. adj agreeing with skrár (f. pl. of skrá).
á reikningnum þínum — á + DAT (location); reikningnum masc. dat. sg. definite suffix; þínum masc. dat. sg. possessive.
Buttons: Halda áfram, Hætta við (native — NOT Continue / Kansella).
Smelltu — 2nd-person sg. imperative of smella (native verb, NOT klikka).
til að skoða þær / til að vera áfram — til að + infinitive construction (purpose).
Status: Vistar breytingarnar þínar… — present tense vistar (3rd person sg. — system is doing). breytingarnar is f. pl. def. ACC; þínar agrees.
ð and þ preserved.

Worked Example — Anglicism rejection

Source: Click here to download the software update.

✗ Wrong (anglicism-heavy):

Klikkaðu hér til að downloada software updatea.

✓ Correct (native Icelandic):

Smelltu hér til að hlaða niður hugbúnaðaruppfærslunni.

Notes:

klikka → smella ✓
downloada → hlaða niður ✓
software → hugbúnaður ✓
update → uppfærsla (here in compound hugbúnaðaruppfærsla = "software-update")
hugbúnaðaruppfærslunni is dative (after hlaða niður which takes dat. object).

Worked Example — Currency (NO decimals)

Source: Subscription: 9.99 EUR / month.

✗ Wrong:

Áskrift: 1.480,00 kr. á mánuði.

✓ Correct (no decimals on ISK):

Áskrift: 1.480 kr. á mánuði.

(Period for thousands; no comma-decimals on Icelandic króna.)

Worked Example — Case-governed prepositions

English	✓ Icelandic
from the user	frá notandanum (dat.)
with the system	með kerfinu (dat.)
to (toward) the page	að síðunni (dat.)
into the system (motion)	í kerfið (acc.)
in the system (location)	í kerfinu (dat.)
onto the screen (motion)	á skjáinn (acc.)
on the screen (location)	á skjánum (dat.)
to (purpose) the user	til notandans (gen.)
about the user	um notandann (acc.)

When in Doubt

Default to is, þú-form, native Icelandic vocabulary (no anglicisms), DD.MM.YYYY dates, ISK with no decimals.
If you see an anglicism (klikka, deleta, seiva, uploada, kompjúter, email, software, browser) → fix to native Icelandic (smella, eyða, vista, hlaða upp, tölva, tölvupóstur, hugbúnaður, vafri).
If you stripped ð to d → restore (maður, not madur).
If you stripped þ to th → restore (þetta, not thetta).
If you stripped æ or ö → restore (bæta, tölva).
If you used þér for formal singular → switch to þú (þér is archaic).
If currency is € / EUR → fix to kr. / ISK (Iceland is not in eurozone).
If currency has decimals (9.99 kr.) → remove decimals (100 kr. — ISK has no aurar).
If a preposition + wrong case → fix to governed case (með → dat., til → gen., frá → dat.).
If you used klika kerfið instead of kerfið (wrong gender) → fix (kerfi is neuter → það kerfi).
If you split a compound (gagna grunnur) → join it (gagnagrunnur).
If verb conjugation is wrong (ég vistar) → fix (ég vista).
If you used English-style plural with no Icelandic plural form → decline noun for number AND case.
If strong/weak adjective mismatch → fix (nýtt kerfið ✗ → nýja kerfið ✓).