This is not a beginner's topic,
but you will hear these "irregularities"
often enough to make you wonder;
so you might as well be told about them now,
so you know they exist,
although you may postpone acquiring these skills until later.
Rule 1: "Ikáw" becomes "ka" when the predicate comes before the subject.
Example: Ikáw ay kumakain. Kumakain ikáw. Kumakain ka.
Rule 2: "ko ikaw" becomes "kita."
Hindi ko nakikita ikáw = Hindi kitá nakikita.