What language is the Celtic language?

The term "Celtic language" is a bit misleading. It's not a single language, but rather a family of languages, much like the Romance languages (Spanish, French, Italian, etc.) or the Germanic languages (English, German, Swedish, etc.).

Here are some key points to understand about Celtic languages:

* Family: They are part of the Indo-European language family, specifically the Insular Celtic branch.

* Branches: Within Insular Celtic, there are two main branches:

* Goidelic: Irish, Scottish Gaelic, Manx

* Brythonic: Welsh, Breton, Cornish (extinct)

* Geographical distribution: Historically, these languages were spoken across much of Western Europe, but today they are mainly confined to Ireland, Scotland, Wales, Brittany (France), and the Isle of Man.

So, to answer your question directly, there is no single "Celtic language". It's a group of related languages with their own individual histories and characteristics.