phonotax UK /ˈfəʊnə(ʊ)taks/US /ˈfoʊnətæks/ noun1 •The total sum of a language's phonological or phonotactic rules.It is crucial for the phoneme structure of Finnish — traditionally /d/ has not been included in the Finnish phonotax, but it fulfils the criteria of a phoneme (Karlsson, 1983: 66-7). — 1990 formsphonotaxes