Desky Kernowek : A complete guide to Cornish
Nicholas Williams (2012)
This book looks at Cornish grammar in detail and includes older variants of the language as well as the more up-to-date version.
Also includes a traditional Cornish phrasebook, a section on verbal usage, a section on spelling and pronunciation, parallel Cornish-English English-Cornish glossaries and a key to all exercises.
In Cornish and English.
COR GRAM 1 Open access