I claim that slash has become the first new coordinator in English in recent history. I use data from naturally observed spontaneous conversation and examples from corpora to demonstrate that slash is an English syntactic coordinator that combines readily with most syntactic categories, both heads and phrasal categories. Slash has a homoreferentiality requirement, where the denotata of the conjuncts must be fused. In cases of non-referring expressions, slash-coordination takes partial characteristics of all coordinands. With a series of three acceptability-judgment experiments, I demonstrate that speakers systematically judge sentences in a way that is consistent with this requirement. And/or is another English coordinator, which is essentially a device to specify the inclusive disjunction in English. It has an additional pragmatic component of `speaker uncertainty' governing its use. These two conjunctions slash and and/or join the small class of coordinating conjunctions in English and help us understand the limits of speaker innovation in functional categories.