Numb tongue is condition that presents itself during an allergic reaction to medicine.
In 2258 of the alternate reality, Cadet James T. Kirk was smuggled on board the USS Enterprise by Dr. Leonard McCoy, who had injected Kirk with a vaccine to protect against Melvaran mud fleas. While in the Enterprise's sickbay, Kirk began to suffer from numb tongue and his hands became enlarged. Kirk attempted to warn Lieutenant Nyota Uhura that the Enterprise was heading into a trap laid by Nero at Vulcan, but his numb tongue prevented him from speaking to her clearly. (Star Trek)