A linguistic mystery surrounding symbol-inscribed stones in Scotland

I found this interisting archaeological article from the BBC:

"The stones are believed to have been carved by members of an ancient people known as the Picts, who thrived in what is now Scotland from the 4th to the 9th Centuries.

These symbols, researchers say, are probably "words" rather than images.

But their conclusions have raised criticism from some linguists."  ...(Cont.)...