What do you call components like -ed or -est that change a word's grammatical function?

The correct answer is inflectional affixes, which are components that modify a word's grammatical function without creating a new word entirely. Inflectional affixes, such as -ed and -est, are added to a base word to indicate tense, number, degree, or comparison. For example, adding -ed to the verb "talk" transforms it into "talked," indicating past tense, and adding -est to the adjective "tall" turns it into "tallest," indicating the superlative degree.

In contrast, derivation affixes change a word's meaning and can form a new word entirely, which is not the case with inflectional affixes. Root affixes, while not a formal term in morphology, typically refer to components that help to create the core meaning of a word rather than modify its function. Syllabic affixes are not standard terminology in linguistic morphology and do not specifically define grammatical changes associated with the components in question. Thus, inflectional affixes are distinct in their role of altering grammatical aspects while maintaining the word’s original identity.