| | | | | | | | | | | Common Celtic | | |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | |
| | | | | | | | | P-Celtic languages | | | | | | | | | | Q-Celtic languages |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | | | | |
| | | | | | Brythonic languages | | | | | | Gaulish | | Celtiberian | | | | | Goidelic |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
| Southwestern Brythonic language | | Pictish | | Old Welsh | | Cumbric | | | | | | | | | | | | Primitive Irish |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | | | | | | |
| Cornish | | Breton | | Middle Welsh | | Lepontic | | Noric | | Galatian | | | Old Irish |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | |
|
| | | | | | | | Welsh | | | | | | | | | | | | | | | Middle Irish | | |
|
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | | | | | | | | | |
| | | | | | | | | | | | | | | | | | | | | Manx | | Irish | | Scottish Gaelic |
|
