epenthetic consonants

An epenthetic sound is one that has no (historical) phonemic basis, and usually no orthographic basis, but is pronounced anyway. Usually it is something we pronounce without meaning to, as a way of easing from one sound to another more fluidly, for instance, saying "for instants." Check your pronunciation; this is certainly how I pronounce it, but the other day I actually say it written that way. The t-insertion is a natural result of trying to go from the voiced alveolar nasal stop /n/ to the voiceless alveolar fricative /s/. The /t/ is somewhere in between -- it retains the stop manner of articulation from the /n/, but acquires the voiceless and oral features of the /s/.

"Pumpkin" is another example of epenthesis. The "p" does not exist historically. Underlying the word is "pumkin," but the "p" jumps in there, just as the t did, keeping the stop articulation of the m and the voiceless, oral qualities of the k. There's something about those (nasal stop)(voiceless non-nasal sound) clusters that's just hard to pronounce. When I see someone write out "for instants," I immediately make a value judgment about the person's intellect, but I don't do the same with "pumpkin" because "pumkin" isn't a word at all. Maybe in a few hundred years "for instance" will have completely transitioned to "for instants."

The epenthetic /p/ in pumpkin also explains the alternative pronunciation "punkin." If the underlying form is "pumkin," the speaker has two options, since the (nasal)(oral) transition is so difficult: one is to insert the epenthetic /p/, the other is to assimilate the nasal consonant to the position of the following stop, hence "punkin," where the n represents a velar nasal. I find it interesting that we have no qualms about pronouncing /n/ as alveolar or velar, yet /m/ we want to pronounce bilabial to the extent that we'll insert epenthetic consonants in "pumpkin" and "hamster."