Old Irish was the Irish language in the Early Middle Ages. People spoke Old Irish in early medieval Ireland, before the year 1000 AD. Old Irish was a Gaelic language, and Gaelic languages like modern Irish and Scottish Gaelic came from it.
People speaking Celtic languages probably first came to Ireland at the start of the Iron Age, about 500 BC. By around 500 AD, people in Ireland all had the same Goidelic language and culture. Speakers of Old Irish began to move to Great Britain as Roman Britain became weaker. Other peoples of the British Isles named these people the Scoti.
Old Irish was the only language in the Goidelic family of languages until Old Irish split into the modern languages of Irish, Scottish Gaelic, and Manx. These languages are Celtic languages and part of the bigger group of Indo-European languages.
- Stevenson, Angus, ed. (2015) . "Old Irish". Oxford Dictionary of English. Oxford Reference (3rd ed.). doi:10.1093/acref/9780199571123.001.0001/m_en_gb0577610. Retrieved 2021-03-05.
- Welch, Robert (2003) . The Concise Oxford Companion to Irish Literature (online ed.). Oxford University Press. doi:10.1093/acref/9780192800800.001.0001/acref-9780192800800-e-1147. ISBN 978-0-19-280080-0.