I already reported this to Ubuntu, but it appears that nobody there is doing anything related to this and I was told that it doesn't help anyone who isn't using Ubuntu, so I am copy-pasting this here.
is what Ä and Ö and Å and all other non ASCII-chars look like to me in WeeChat 0.4.4-dev (git: v0.4.3-447-ge901d14) [compiled on Apr 12 2014 10:50:16]. My WeeChat was configured to read iso-8859-1 and UTF-8 and I was unable to see Ä and Ö -letters that are used in Finnish a lot from XChat user.
They told me that they were using UTF-8 (as they should), but I couldn't see those messages even after setting my client to only understand UTF-8.
When invistigating more they told that they were using charset "IRC (Latin/Unicode Hybrid)" instead of UTF-8 and said wrongly claimed that it's same as UTF-8. I corrected them and then they tested UTF-8 from the charset list and everything started working.
I also did these tests with XChat which I installed just to see if this happens for me too, so I could file this bug report.
So please stop using that weird charset as default and use UTF-8 which everyone should be using already. As far as I know HexChat is using it as default too see ( https://github.com/hexchat/hexchat/issues/282 ), but I cannot make people change their IRC clients much easier than fix their charter encodings.
Addition: It's also confusing to people that this charset is default instead of UTF-8 as they believe that they are really using UTF-8.
EDIT: Added link to the HexChat issue.
DistroRelease: Ubuntu 13.10
Package: xchat 2.8.8-7.1ubuntu2
ProcVersionSignature: Ubuntu 3.11.0-19.33-generic 220.127.116.11
Uname: Linux 3.11.0-19-generic x86_64
Date: Sat Apr 12 17:50:25 2014
InstallationDate: Installed on 2014-02-01 (70 days ago)
InstallationMedia: Lubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
UpgradeStatus: No upgrade log present (probably fresh install)