tense (for instance -vde: simple past, -u:a simple future, with added increments -vde:aka 'further past', -u:ana 'further future), and mood (generally in that order), etc. are suffixal, along with the two 'benefactive' suffixes -a:gu: 'for self', -ya:gu: 'for another'. Number within the verb (number of subjects or acts) can be encoded by overt marking (once -ata, twice -a:pai/-pikin-, several times -a:misiu:, plural -isin-/-u:sin-, or even none -apisiu:) or the many different distinct plural verbs (for instance mvni 'sg. to stand', palana 'pl. to stand'; ata 'sg. to take, convey', tu:mi:na 'pl. to take, convey'). Ex. i:nan haian kvndaiananima ha-ts-tu:-uhr-gaiat-u:sin-de:-aka a:nan 'We (haian) were making them (kvndaiananima) take (uhr < ata 'take') the boat (a:nan) during (ts- circumstantial plus -n locative on) the winter (i:na) a while ago'. A handful of verbs form doublets where one of the pair seems to have an unproductive reversative suffix possibly related to the form -a:gu: '(do) for oneself'. For instance ma:na 'to lend', ma:na:ku: 'to borrow'. In addition to normal serialization Yahgan also exhibits complex verb stems of a type relatively common in western North America, where the main verb is flanked by instrument/body part manner of action prefixes and pathway/position suffixes. The prefixes are part of a larger, more open system of elements marking various kinds of causes or motivations, grading off into more grammaticalized voice marking. Many of the path/position suffixes (especially posture verbs) do double duty as sources for more grammaticalized aspectual morphology. Tense suffixes seem to derive historically from horizontal motion verbs, and together with the more vertical postural aspect forms, make an interesting Cartesian-style coordinate system for dealing with the temporal dimension. Example stems are: -aku:-pung-kvna-, -aku:- 'by striking' (itself from aki 'strike' plus -u:- permissive/causative), -(a)pvna-'kill/die', -kvna 'in a boat or afloat', meaning 'to kill by striking while afloat'. -alagvnat-u:-tekil-uhr-man-a:tsikvri- 'to stand by watching (-alagvnat-) and let (-u:) step completely (-tekil-ata-) out (-man-a:tsikvri-) (say a person one does not like out of the house into the line of gunfire without warning or stopping him). A small number of commonly used verb roots have irregular present tenses. Instead of dropping the final vowel (triggering reductive processes) these forms instead add -ata after the vowel is dropped. Examples: mu:tu: 'to sit'/'to be', present mu:ta (from mu:t-ata), wi:a 'to lie'/'to be', present wi:ata, kvna 'to float'/'to be', present ga:rata. In the last example note that this seemingly suppletive present may in