The Icelandic wikipedia currently has no interwiki links on its
century and decade articles, this is because Icelandic uses a system
for decades and centuries which probably not alot (if any) languages
use, at least not the ones i've surveyed, our decades and centuries
are "off" by one year from "conventional" systems, we therefore cannot
link to them since the two articles would not describe the same
period.
A decade in Icelandic starts at x where x is a number ending in one
and ends nine years later, so for example the period 1991–2000 is the
"tenth decade" of the twentieth century. This is unlike English where
a decade would be the period from 1990 to 1999 and be called the
"1990s" or "nineties" for short.
Similarly, the "twentieth century" begins in 1901 and ends in 2000,
unlike the English twentieth century which begins in 1900 and ends in
1999.
This system is at least not used in Danish, Norwegian, Faroese,
Swedish, German, English, Spanish, french, Italian, Dutch, polish.
So, if any of you know another language which uses the same info reply
to this email, and we can then link to it.