This suffix was used to join two words, phrases or clauses together. It was attached to the word which should be joined to the previous, which was always the first word of the second clause or phrase. If the first word was a compound or had a prefix, the suffix was infixed after the first part of the compound or after the prefix, effectively splitting the word in two.
It was also used to form several distributives by attaching it to existing interrogative words.
When attached to a word that ended in an obstruent (and possibly other consonants as well), an epenthetic -u- was inserted, which caused the suffix to be delabialised through normal phonetic rules, turning it into *-uh.