KGT p. 88, as food.

The Ruk'evet word for "be clumsy" is jat, which is phonetically identical to the noun meaning "tongue." Even though this is probably just a coincidence, there is a slang term jat, used throughout the Empire but somewhat more frequently in the areas near Ruk'evet, which means "speak incoherently, mumble," a notion with negative connotations for Klingons. Enunciating Klingon clearly is always important, but one should take extra care to not accidentally say jat ("mumble") when intending the similar-sounding ja' ("say"), jatlh ("speak"), or jach ("yell").