You'd do better to read this article:

http://www.albanach.org/kilt.html

The adoption of the kilt by other Celtic peoples is a relatively new one; part of various nationalist movements by the various Celtic peoples. The Irish were the first to do it in the late 19th century, followed by the Welsh, Cornish, Manx, Bretons, etc. in the 20th century.

Regards,

Todd