古凱爾特語, or Old Celtic, is an ancient language that was spoken by the Celtic peoples in parts of Europe, particularly in regions that are now Ireland, Scotland, and Wales. It is part of the larger Celtic language family, which also includes languages like Welsh and Irish. This language is primarily known from inscriptions and early texts, and it played a significant role in the cultural and linguistic development of the Celtic tribes. Although it is no longer spoken today, its influence can still be seen in modern Celtic languages and in various place names across Europe.