Strong Verbs Present Tense Vowel Shift

May 11, 2024
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Some strong verbs change their vowel when you conjugate them. That sounds confusing. At least we can put a name on it: i-shift (or Germanic umlaut, or i-umlaut, or any of a dozen other synonyms, or i-hljóðvarp or B-víxl in Icelandic: let’s stick with i-shift for simplicity).

You can thank ancient history for this, and when I say ancient, I mean ancient – we're talking Iron Age here. The i-shift is so old, it isn't even an Icelandic thing – it's actually a Germanic thing, and you can see it in English, too. Mouse, mice – man, men – fox, vixen – sing, sang, sung; these are all i-shifts. So we don’t get to complain about it being in Icelandic, ok?

In ye olde times, there was a rule in Germanic languages that if an i appeared in a word, it affected (or shifted) the vowel before it, making it more similar to an i sound. This is creatively called an i-shift.

This affected all sorts of words - not just verbs - but today we’re narrowing our focus to just verbs.

In modern Icelandic, this rule isn’t active - hell, most of the words where we see i-shift don’t even have an i anymore - but its effects sure as hell have stuck around. The upshot is that because of a rule in Proto-Norse of the Iron Age, you get to memorise some wacky vowel shifts to conjugate strong verbs!

Rule of Thumb 

Basically, it works like this.

i-shift only affects the singular conjugations, NOT the plural conjugations.

You do still have to remember how the endings work. This table of endings only has words whose stem vowel doesn’t change, so you can focus on the endings.

 With that said, there’s really nothing for it but taking a look at examples. 

a, o, ö > e

This is the largest and most common category, occurring about six times as often as the next most common (á > æ) and about 60 times as often as the smallest one (au > ey). If you’re going to learn anything, then you should learn this category.

Notice the u-shift in the first person plural (við) for verbs with an a in the stem, like hafa and fara.

á > æ

jó, jú, ú > ý

au > ey

This is really a tiny group, and the words in it are really not that important. If you feel like slacking off anywhere, this is where you can do it.

Sjá and þvo

Sjá and þvo don’t really fit into any category. They do their own thing, the little rebels.


Strong verbs can change their vowel in the present tense, but it only affects the singular. You just gotta memorise these, but don’t worry: after a little while you’ll develop a feeling for it.