Here's fun.

http://skolavefurinn.is/lok/almennt/ljodskald_man/Torarinn_Eldjarn/leskaflar/Keflvikingasaga/Kefli_sagan.htm

Keflvíkingasaga is a satirical short story by Þórarin Eldjárn in which
a wandering Viking arrives in present-day Iceland, along with his
family and thralls, where he attempts to settle and "take land". It
ends in disaster, obviously! This is how Þórarin imagines a Modern
Iceland speaker's first encounter with Old Norse as a living language:

Bjartmar var íslenskukennari og fullyrti við félaga sína að maðurinn
hefði mælt á norræna tungu. Að vísu hafði honum ekki tekist að skilja
eitt einasta orð, en hljóðdvöl kvaðst hann hafa skynjað óbylta og
glögglega heyrt að kveðið var í nef og gamla sérhljóðakerfið enn í
fullu gildi að öðru leyti, en þó talsvert frábrugðið því sem fræðimenn
hefðu gert sér í hugarlund hingað til.

Bjartmar was an Icelandic teacher and asserted to his companions that
the man had spoken in Old Norse. It was true he hadn't managed to
understand a single word, but he said he'd perceived the [distinctions
in] vowel length unaltered, and clearly heard the nasal pronunciation,
and the old vowel system still in full effect in other ways, although
significantly different from how scholars had hitherto imagined it.

(Note: the uncouth settler seems to have lost his ability to
distinguish between short and long vowels later, in the verse he makes
to celebrate cutting off Bjartmar's head to use as a football. There
`skori', `þori' and `þusi' are treated metrically as having long root
vowels, as they do in Modern Icelandic.)