Caballo is an island in the entrance to the Philippines' Manila Bay. Caballo, along with the larger Corregidor (2 km to the north), separates the harbor entrance into a northern and southern channel. It is doubtful that Caballo measures even 5 km² in area.
... "they are in me".
"-aham" (I) in the second line is nominative. na caaham =
"...and not I....", meaning "but I am not...".
"teshv-" (in/at/by them) at th ...