Sila comes from the French celui-là and represents a regional variant from the lateral zones of Haiti, especially Northern Haiti.
Isit la is used to refer to something that cannot be seen, but is not unique. Forms with isit/sit/isi (comprising plural forms (chat isi a yo; chat isi yo)) have been located in different villages in the North and South of Haiti as is shown in the Atlas linguistique d’Haïti (Fattier 1998). There are also combinations of the kind chat bò isit la (> bord + ici; 'side' + 'here').
Source: Fattier 1998: vol. 2, p. 845
Source: Fattier 2000: 42-45