"ē_r ⇌ _m / [-spread -labdent]*[b-c-d-g-k-l-p-q-r-s-t-z][i-u]_tu_" . . . "ē_r ⇌ _m / [-spread -labdent]*[b-c-d-g-k-l-p-q-r-s-t-z][i-u]_tu_" . .