or /é/, and the non-auxiliary verb subject-verb agreement also changes in agreement with the negation, despite the fact that only the auxiliary undergoes negation. This double variation is shown in 1a-b), where I in the sentence gloss indicates the agreement affix /í/. In these examples, the verbs are undergoing morphological changes in order to be in agreement with the negation, regardless of whether they are directly negated or not. Honorific agreement In certain languages, verb agreement can be controlled by formality, as with Korean subject honorific agreement. When the subject of the sentence is a respected person, the honorific suffix si occurs after the verb root and the honorific subject case marker is Kkeyse in as seen in (3a). Moreover, honorific agreement is optional, as seen in(3b)., There is a debate about whether Korean subject honorific marking is authentic agreement. The debate stems from that fact that languages where verbs show person agreement, the agreement is obligatory. Based on this reason, some scholars contend that since honorific marking is optional, it is not an instance of agreement. However, other scholars others argue that it is indeed agreement. A fundamental quality about honorific marking that is often overlooked is the fact that is it possible only with a human referent. Consequently, as shown by the examples in (4), when the subject is non-human, honorific agreement is ungrammatical. Phi features as categorizing features Phi-features can also be considered the silent features that determine whether a root word is a noun or a verb. This is called the noun-verb distinction of Distributed Morphology. The table below describes how category classes are organized by their Nominal or Verbal characteristics. Definitions for these four categories of predicates have been described as follows: A verbal predicate has a predicative use only; a nominal predicate can be used as the head of a term; an adjectival predicate can be used as a modifier of a nominal head; a preposition acts as a term-predicate for which the noun is still the head; an adverbial (not shown below) predicate can be used as a modifier of a non-nominal head. X-bar theory approaches categorical features in this way: when a head X selects its complement to project to X', the XP that it projects to then is a combination of the head X and all of its categorical features, those being either nominal, verbal, adjectival or prepositional features. It has