▁including ▁their ▁myth ology , ▁political ▁structure , ▁and ▁village ▁formation . ▁Sch uster ▁ 1 9 7 6 ▁published ▁a ▁word list ▁within ▁his ▁eth n ography , ▁but ▁otherwise ▁there ▁was ▁not ▁much ▁lingu istic ▁study ▁in ▁that ▁time ▁period . ▁He inen ▁( 1 9 8 3 – 1 9 8 4 ) ▁published ▁a ▁grammar ▁sketch ▁c ouch ed ▁in ▁his ▁mostly ▁eth n ographic ▁study ; ▁G uss ▁( 1 9 8 6 ) ▁includes ▁some ▁texts ▁in ▁the ▁language ▁in ▁his ▁publication ▁on ▁or al ▁tradition ; ▁and ▁Hall ▁( 1 9 8 8 ) ▁published ▁two ▁volumes ▁on ▁morph os yntax ▁and ▁disc ourse ▁analysis . ▁Later , ▁Hall ▁( 1 9 9 1 ) ▁looked ▁at ▁trans itivity ▁in ▁ver bs , ▁amid ▁many ▁more ▁eth n ographic ▁studies , ▁and ▁Ch avier ▁( 1 9 9 9 ) ▁studied ▁some ▁further ▁aspects ▁of ▁the ▁morph ology . ▁A ▁dictionary ▁was ▁published ▁on ▁CD - ROM , ▁and ▁most ▁recently , ▁Nat ál ia ▁C á cer es ’ ▁MA ▁th esis ▁is ▁a ▁brief ▁over view ▁of ▁the ▁soci ol ingu istic ▁profile ▁of ▁the ▁Ye ' ku ana , ▁while ▁her ▁doctor al ▁dis sert ation ▁presents ▁a ▁more ▁complete ▁descript ive ▁grammar . ▁C out inho ▁( 2 0 1 3 ) ▁has ▁also ▁expl ored ▁the ▁number ▁system ▁of ▁Ye ' ku ana , ▁from ▁a ▁typ ological ▁perspective . ▁ ▁Ph on ology ▁ ▁Ada pt ed ▁from ▁C á