There a lot of novel, neat words that are pretty lyrical and that I had not heard before, but this is not an exhaustive presentation of things that defy translation. What would you include in an alphabetical format?
Idiosyncratic and family pet-names names for things and concepts or a how about list of the weird jingo and abbreviations of concepts hard to visualize thrown around freely at the office, those words that would be completely foreign sounding and unassailable to a non-native speaker?