Propataireachd has as its root word, the English "prop"... "-atair" is equivalent to English "-er", and "-eachd" is perhaps equivalent to "-ing".
pɹəpɐtˈɛɹætʃd hɐz æz ɪts ɹˈuːt wˈɜːd, ðɪ ˈɪŋɡlɪʃ "pɹˈɑːp"... "ˈæɾɛɹ" ɪz ɪkwˈɪvələnt tʊ ˈɪŋɡlɪʃ "ˈɜː", ænd "ˈiːtʃd" ɪz pɚhˈæps ɪkwˈɪvələnt tuː "ˈɪŋ".