(links)
Cumbric at Wikipedia
Lo and Behold!
Vocabulary of Older Scots
Medieval Names Archive
Mary Jone's Celtic Literature Collective
Welsh Language at Wikipedia
Medieval Welsh (Heather Rose Jones)
Welsh at Omniglot
Dictionaries etc
Prifysgol Caerdydd
Prifysgol Cymru Y Drindod Dewi Sant
Y Gwe-Eiriadur
Geiriadur yr Academi
Learning
Learn Welsh at the BBC
BBC's Big Welsh Challenge with interactive course
Say Something In Welsh
Community
Forum Wales
Irish Language at Wikipedia
Talk Irish (includes forum)
Irish Grammar etc
Irish at Omniglot
Irish Dictionary Online
Gramadach Lexicon at Ceantar.org
eDIL
Focal
Old Irish Lessons at UTexas
Learn Irish at the BBC
Pronunciation Guide
Info
Cornish Language at Wikipedia
Handbook of the Cornish Language
Maga - Cornish Language Partnership
Standard Written Form Downloads
The Cornish Bible
Cornish at Omniglot
Blas Kernewek at the BBC
Kewkowsva an Gernewegva
Sabhal Mòr Ostaig
Gaelic at Omniglot
Akerbeltz
MacBain's Etymological Dictionary at Ceantar.org
Am Faclair Beag
Searchable Dictionary at SMO
Learn Gaelic at the BBC
Fòram na Gàidhlig
Kervarker.org
Breton Language at Wikipedia
Breton at Omniglot
English/Breton Lexicon at Wordgumbo
French/Breton Dictionary, Geriadur.com
Breton/English Lexicon
100 Words for the Internet
Lessons at Kervarker.org
Gaelg
Manx at Wikipedia
Manx at Omniglot
Online Manx Dictionary
Learn Manx