Addá and awán — two of the most-used words in Ilokano, for existence, presence, and possession.
addá states that something exists or is present (or that someone possesses something); awán states the opposite — that it doesn't exist, isn't there, or isn't possessed. Both are confirmed entries in this app's dictionary, listed as particles.
Addá táo idiáy baláy.
There is someone in the house.
Awán táo idiáy baláy.
There is no one in the house.
Move the noun phrase to the front, followed by ti and the rest of the sentence, and it becomes the subject of a definite or indefinite sentence instead — same tools from the word-order lesson.
Diáy ubíng ti addá idiáy baláy.
It is the child who is in the house.
awán also combines with a goal-focus verb to mean "didn't do (it) at all" — a very natural way to answer a question in the negative.
Awán ti ginátang ko idiáy íli.
I did not buy anything in town.
Grammar: Ch. 7.1, Existential Sentences, from Constantino's Ilokano Reference Grammar (1971, CC BY-NC-SA 4.0).