The Collaborative International Dictionary
Linguistical
Linguistic \Lin*guis"tic\ (l[i^][ng]*gw[i^]s"t[i^]k), Linguistical \Lin*guis"tic*al\ (l[i^][ng]*gw[i^]s"t[i^]*kal), a. Of or pertaining to language; relating to linguistics, or to the affinities of languages.
Wiktionary
linguistical
a. linguistic
Usage examples of "linguistical".
So why did she feel, as they said in the old saw Keff had once dug up in his linguistical research, as if a goose had walked over her grave?