Llawlyfr Hen Gymraeg (‘Old Welsh Handbook’) by Dr Alexander Falileyev is the first comprehensive description of Old Welsh to appear in the Welsh language.
It is published by the Coleg Cymraeg Cenedlaethol and was launched at Aberystwyth University on Tuesday 1 March.
Old Welsh refers to the period between the ninth century and the early twelfth century in the history of the Welsh language.
Although books on Old Welsh are already available in English, French and Russian, there were no Welsh books until the publication of this e-book by the Coleg Cymraeg Cenedlaethol.
Llawlyfr Hen Gymraeg provides the first opportunity for Welsh speakers to learn about some of the earliest known examples of texts in their language.
Dr Alexander Falileyev, a native of St. Petersburg, Russia, is an expert on the Celtic languages.
He has published extensively on the place names and personal names of ancient European Celts, and on the language and literature of medieval Wales.
Llawlyfr Hen Gymraeg is an adaptation of an Old Welsh grammar by Alexander Falileyev published in Russian in 2002 and in French in 2008.
Dr Falileyev has adapted the text for a Welsh audience and has incorporated the latest research findings.
It contains detailed descriptions of known texts, with a full bibliography, chapters on phonology, grammar and syntax of the language, and a selection of edited texts with comprehensive notes and vocabulary.
This volume follows handbooks by Henry Lewis on Middle Breton and Middle Cornish and by Melville Richards on Old Irish published during the 1920s and 30s.
The latest volume is the first in a new series edited by Dr Simon Rodway from the Department of Welsh, Aberystwyth University.
Dr Rodway said: "Henry Lewis and Melville Richards’ short volumes are very useful handbooks: they attest to the fact that students were studying medieval Celtic languages through the medium of Welsh during the first decades of the last century. This is still true today, but students often have to turn to English resources if they want to benefit from the latest research in the field. The goal of this new series is to change that, and there's no better place to start than with the pioneering work of Dr Falileyev on Old Welsh, essential reading for anyone interested in this exciting stage of our language."
The book is available as a free e-book from the Coleg Cymraeg Cenedlaethol’s online resource library