Olwen is a family of free fonts based on the Bitstream Vera fonts. It aims to extend the coverage of the Vera fonts while remaining true to the original style.
Olwen's additional glyphs have been merged into the DejaVu fonts, another extension of Vera.
In addition to the characters covered by Vera, Olwen covers the following characters:
Ŵ ŵ Ŷ ŷ Ÿ Ẁ ẁ Ẃ ẃ Ẅ ẅ Ỳ ỳ
This means that Olwen supports the Welsh language.
It's simplest to install the fonts if you're using a system based on
Fontconfig and you
just want to install them for yourself. (Systems that use Fontconfig include
recent versions of GNOME and KDE.) In that case, you can simply put the .ttf
files in a directory called ".fonts" in your home directory and run the
command "fc-cache -f".
If you're not using Fontconfig, or if you want to install the fonts for the whole system, you'll have to refer to some other documentation, I'm afraid. Or, if you have a Debian system, you could try the packages mentioned below.
Debian packages are available.