This looks very like
Nadelik Lowen ha Blydhen Nowydh Da
which is
Merry Christmas and a Happy New Year
in Cornish.*
* (Standard Written Form: other spellings exist)
The phrase "nadelik looan blethen noweth" is in the Cornish language. It means "Merry Christmas and a Happy New Year." Cornish is a Celtic language spoken in Cornwall, a region in the southwest of England.
What does nadelik looan na looan blethen noweth mean? It actually is Cornish for: Merry Christmas and a Happy New Year!
This is Cornish!
Cornish.
Cornish
This is Cornish, very similar to Welsh
Cornish
"noweth" is an old English word that means "knew" or "knew not." It is rarely used today and is considered archaic.
Gwas Kenethlow. has written: 'Grammar for the first grade and the auxiliary verbs' 'Grammar for the second grade' 'Grammar for the first frade' 'Whethlow Noweth Ha Coth' 'Hwedhlow nowydh ha koth ='