Yesterday we took my son Aran, who's now three and a half, to Legoland, where he got to ride his first rollercoaster, since he's now just tall enough for the smaller ones. As we spun around the track, he leaned against me and shrieked with a mixture of trepidation and glee. Afterwards, he proudly told me, "I scrome (/skro:m/) on the roller coaster," a form that made me sit up and take note, as it's an innovative irregular past form of "scream" that I'm pretty sure he came up with himself, although I can't completely rule out the possibility that he heard it at his preschool. This afternoon, I tried to confirm that this wasn't a nonce form with a little elicitation. It took a little prompting, but he volunteered /skro:m/ without my actually giving him the form: ME: Aran, yesterday, when you went on the roller coaster, what did you do? Aran: I got on the roller coaster. ME: Did you scream? Aran: I did scream. ME: You did what? Aran: I scrome. The interesting question is how exactly how he settled on /skro:m/. Like most (all?) young children learning English, he's gone through the stage of over-generalizing past-tense and past participial forms, applying -ed to the end of verbs that have irregular paradigms (I goed, etc.). He's starting to outgrow that now, because he's been using the irregular forms much more often in the last month or two, although I just heard him say, "The sail is teared" as I was writing this. To create innovative irregular forms is much less common, but there are patterns of vowel gradation that repeat (e.g., swim/swam/swum; ring/rang/rung). You would expect that it's the result of analogy one of these systems. But there aren't very many verbs with a gradation of /i:/, /o:/ (steel/stole is the only one I can come up with that he knows), and that seems like a very slender basis on which to coin a new form. On the other hand, his linguistic inventiveness never ceases to amaze me. That's one of the great things about raising a child. [Update 1/21: today, he came out with "I clomb it" (i.e., climbed). He appears to be using vowel ablaut at least semi-productively as a past-tense marker. Weirdly wonderful. Update 2/12: my wife reports hearing "drome" as the past tense of dream.]