KGT p. 35: The primary difference between the speech of older and younger Klingons, however, lies in the choice of vocabulary. Younger Klingons describe some of the vocabulary used by their elders as mu'mey Doy' ("tired words"),preferring to use what they call mu'mey ghoQ ("fresh words") or even Hol ghoQ ("fresh language"). (The word ghoQ ["fresh"], in its most narrow usage, applies to just-killed meat). Perhaps "slang" is a good translation of mu'mey ghoQ. Some older Klingons incorporate some of the mu'mey ghoQ into their own speech, though some claim not to understand the mu'mey ghoQ at all (nor are they quite sure what the term itself means.)