"Harvest Home" by Tryon has a character whose tongue is cut off and the wound tended by non-medical people. And "A Game of Thrones" does as well.
It's not specified in either one how much tongue is removed. In Harvest Home they mention that the wound was stitched up. The character was quite disabled, stay-in-bed weak for months, and continued to have trouble eating, choking often. I no longer remember if he ever resumed his previous activities.
Losing the last inch is going to leave a pretty severe speech impediment. The person will be able to make the lip sounds and the open sounds but none of the consonants which use the tongue, like D, TH, S, G, TCH, L, N and maybe others. (Good thing I'm sitting here alone making these unintelligible noises, rather than at the library or office, huh?)
I would think that even after healing, they're going to have issues moving food around in their mouth and may need to modify their diet and the size of each bite.
Maryn, who'll keep her tongue, if that's okay