We specifically looked at sika and claimed that it is different from other Japanese NPIs.
14Taro-sika ookina-kemusi-no iru ringo-o tabe-nai Taro-SIKA big-worm-be apple-OBJ eat-NEG Only Taro eats an apple which a big worm is in' (15) Taro-sika kasikoi-tori-kara kakureta ookina-kemusi-no iru ringo-o tabe-nai Taro-SIKA wise-bird-from hiding big-worm-be apple-OBJ eat-NEG Only Taro eats an apple which a big worm that is hiding from a wise bird is in' sika construction can embed another sika construction, as can be seen in the following: (16) Taro-sikal Ken-ga eigo-sika2 ie-de hanas-anai2 koto-o sir-anail Taro-SIKA Ken-SUBJ English-SIKA house-at speak-NEG fact-OBJ know-NEG Only Taro knows that Ken speaks only English at home' Taro-sika is interpreted as associated with sir-anai, hence the same superscript, while the internally embedded eigo-sika is interpreted as associated with hanas-anai.