yi- this prefix is used with the words "gesdi" or "tla" to negate a verb. When used alone it expresses the conditional "if", "can", or "could". yagow'tiha - if he sees...
tsi- - "I", this is an "A" Class bound pronoun, used before a consonant.
-gata- - present verb stem for "know"
-ha - present tense suffix. In conversation the "ha" is often dropped, thus "yitsigata".