The fourth chapter contains conjugation rules for building verbs that have an irregular verb-ending. All verbs, for example, that end on "car" are built following the rules of the entry ~car.
Chapter 1: General Information
Chapter 2: The regular verbs
Chapter 3: Vocal-dependent, irregular verbs
Chapter 4: The irregular verb-endings
Chapter 5: The irregular verbs
Chapter 6: Appendix