what language is this?

Can anyone identify this language?

<<Ph'nglui mglw'nafh Cthulhu, R'lyeh wgah'nagl fhtagn>>

Is it Irish or Gaelic? Thanks

http://en.wiktionary.org/wiki/ph%27nglui_mglw%27nafh_Cthulhu_R%27lyeh_wgah%27nagl_fhtagn