And "discord" means "disagreement", "lack of harmony", "arguments" in English. Even weirder name for a chat application in an even more commonly used language.
"Slack" associates pretty strongly with "slack off" (get no work done) too, so that one's also strange.
"Slack" associates pretty strongly with "slack off" (get no work done) too, so that one's also strange.
I think "Zulip" has the best naming of all these.