If you hate it when nouns are used as verbs, it's time to consider that the words that and up can be many different parts of speech.
Anthropologist Edward Sapir once wrote, “unfortunately, or luckily, no language is tyrannically consistent. All grammars leak.” Sapir was talking about the irregularities of language. For me, this leakiness is especially evident in what I think of as doppelgrammar words.
Many of our most common words have come to serve more than a single grammatical role, so a word serving one part of speech will often have a homonym—a grammatical doppelganger—that serves as a different part of speech. Often this arises from what is called functional shift, when we take a noun and make it into a verb as in to adult or to gym. This shiftiness makes it hard, and perhaps impossible, to think of a word as having just one categorization.
Here’s an example. Recently, a friend told me that her daughter’s teacher had told her to never use the word that. She wondered if the advice was legit.
What Part of Speech Is ‘That’?
It depends, I said, which that we are talking about. This humble four-letter word can serve as a pronoun, adjective, conjunction or even an adverb. When we say “Hand me that,” the word is functioning as a demonstrative pronoun, referring to something oriented away from the speaker (as opposed to this). But if we say, “Hand me that book,” it is functioning as an adjective, though again indicating orientation. If we say “Have you seen the person that was just here,” the word is a pronoun again, a relative pronoun linking the noun person to the clause that was just here. Whew.
That can also be a straight up subordinating conjunction introducing a clause functioning as a noun: “I told you that I would be right back.” This that is the one that writers often cut to make prose move along more quickly: “I told you I would be right back” is often preferred on grounds of conciseness. This is what my friends’ daughter’s teacher was talking about. And, last but not least, that can even be an intensifying adverb, as in “Yes, it is that complicated.”
Now, we might quibble about these characterizations—perhaps the adjective that and the demonstrative pronoun that are related, “Hand me that” being a reduced form of “Hand me that book.” But the larger point is pretty clear: our simplest words serve more than a single function. Grammar leaks, and words have doppelgangers.