expression of habit. All verbs can, but do not have to, be marked as imperfective with the auxiliary ya, intransitives further requiring the prefix -x. In the sentence Ya x-weʼ-on ("I eat (habitually)" or "I'm going to eat (now)"), Ya x- marks the verb weʼ ("to eat") as both imperfective and intransitive, while -on marks both case (absolutive) and person/number (first singular). Compare this to the sentence Ya j-naʼ ("I know that") in which the transitive verb -naʼ ("to know [something]") does not receive -x but instead receives, like all transitive verbs, two person/number markers (j-, first person ergative, and -Ø, third person absolutive). In reality the auxiliary ya is a reduced form of the imperfective marker yak, though variation and conditioning vary greatly across dialects. In the Bachajón dialect it has been morphologically reanalyzed as a prefix (rather than an auxiliary or preverb), but only when the verb is marked for the second-person ergative. Thus, to say "You know that," speakers from Bachajón may say Ya k-a-naʼ, the -k occurring as a verbal prefix before person/case marker a-, whereas other speakers would prefer Yak a-naʼ. The independence of ya and k in this dialect is shown by the fact that they may be separated by clitics, as in Yato k-a-naʼ ("You already know that": clitic =to "already"). Further, in other dialects ya is commonly reduced to [i], though not systematically. It is, however, systematically absent after the negation ma(ʼ). Perfective The perfective aspect is used to present an event as bound or completed. Intransitive verbs do not take any markers in the perfective aspect, and an intransitive verb without aspectual markers is unambiguously understood as perfective. Compare the following two sentences, each with the intransitive verb bajtʼ ("go"), the first perfective and the second imperfective: Bajtʼ ta Kʼankujkʼ ("He went to Cancuc") Ya x-bajtʼ ta Kʼanjujkʼ ("He's going to go to Cancuc/He will go to Cancuc") Transitive verbs in the perfective aspect are marked with the auxiliary preverb la ~ laj, the full form laj used in the Oxchuc dialect only when the auxiliary appears alone, as an affirmation. This auxiliary historically comes from the intransitive verb laj ("finish, die"). Certain other "aspectual" or movement-oriented verbs, such as tal ("come") have similarly become usable as auxiliaries, and when used as such appear without person markers, which appear on the following verb. Though tense is not morphologically indicated in Tzeltal,