Nanette is a preschooler who says, 'We goed to the store.' Which of the following features of language development does Nanette's utterance demonstrate?

Underextension occurs when a child uses a word too narrowly, applying it to fewer instances than it actually describes. For example, if Nanette only referred to her pet dog as a "dog" and not to all dogs, that would illustrate underextension. Her use of "goed" does not reflect this concept.

Overextension happens when a child applies a word too broadly, such as calling all four-legged animals "dog." Nanette's mistake with "goed" does not fit this description, as her utterance specifically demonstrates the incorrect application of a grammatical rule rather than a word being used too broadly.

Telegraphic speech involves using short and simple phrases that omit non-essential elements, typically seen in two-word combinations (e.g., "want cookie"). Nanette's utterance is a single verb form rather than a reduced phrase, which means it does not exemplify telegraphic speech.

Fast mapping is a process where children quickly learn new words and their meanings after only a few exposures. Nanette's incorrect verb form does not demonstrate this process, as it relates more to her application of grammatical rules rather than vocabulary acquisition.