Children are born knowing a Universal Grammar

The argument

Children acquire their first language(s) with the help of a Universal Grammar (UG), a set of rules that children are born knowing that govern how all human languages work. The innate presence of a UG in children's brains is the best way of explaining why children learn language in the way that they do as well as why typical children easily become fluent in their first language(s) without any formal teaching. There is a host of evidence to support the theory of Universal Grammar. First, humans are the only species that we know of that have language, so there must be something innately within us allowing us to learn language fully that is missing from other animals, plants, etc. Second, every language appears to share certain properties, and there are examples of distant, completely unrelated languages, like Japanese and Quechua, that look remarkably like one another. Third, if two children are exposed to different varieties of the same language--or even if one of the two has little to no exposure to certain sentence structures--both children will yield the same understanding of the language and its rules. Lastly, regardless of the culture in which a child is raised or the language(s) learned, all children go through the same stages of language learning in the same order. There have been many more arguments put forth in support of the UG hypothesis over the years, but the core point of all of them is this: even with minimal exposure and little to no correction and instruction, children learn language and its rules through their innate Universal Grammar.

Context

The theory of Universal Grammar (UG) does not refer to the grammatical rules of a specific language but rather all languages in general. It states that there are grammatical rules that govern all languages and that children are born with this knowledge. While this idea is generally attributed to the linguist Noam Chomsky, there are many other people who have discussed it before him, such as Plato, Panini, René Descartes, Denis Diderot, and Wilhelm von Humboldt.

Premises

Counter-arguments

This argument presents several pieces of "evidence" that are, in fact, invalid. For one, the mere fact that humans are seemingly the only species capable of complex communication--which is a debate in and of itself--does not automatically mean that children are born with UG. Next, while there are some languages that are similar despite their unrelatedness, a true Universal Grammar that unites all languages is debatable at best. Some researchers even call this concept a myth. The fact that all speakers of a language eventually have the same linguistic and grammatical awareness is equally false: studies like Street and Dąbrowska's 2010 paper show that adult speakers of the same language can have very different perceptions about what is grammatical and what isn't. Children also do not always follow the exact same pattern of language acquisition. There is a multitude of differences cross-linguistically and even within the same language. Finally, research has demonstrated that teaching and instruction is sometimes necessary even for typically developing children, which invalidates one of the Universal Grammar hypothesis's core tenets.

Rejecting the premises

[Rejecting P1] Ease of acquisition without formal teaching establishes only that something makes acquisition possible, not that the something is an innate grammar. Children also learn to walk, read faces and infer social intent without instruction, and no dedicated rule system is posited for those. Naming Universal Grammar the "best explanation" skips the competitors it would have to beat — general statistical learning over enormous exposure, and the possibility that languages are themselves shaped over time by what young children can easily learn. [Rejecting P2] Each of the four supports is weaker than presented. Uniqueness to humans marks a species difference without identifying its mechanism. Shared core properties across unrelated tongues is the disputed claim, not evidence for it, and the list of candidate universals has narrowed as more languages have been described. That all speakers reach the same understanding is contradicted by work finding measurable differences in grammatical attainment among adult native speakers of one language, differences that track exposure and schooling. Common stages in a common order can follow from the order in which sounds and meanings become learnable, together with broadly similar input. [Rejecting C] The conclusion restates the premise it most needs to establish: that children are "born knowing" a grammar is the innateness hypothesis itself, so the argument turns on its own claim. What the observations support is that language acquisition is reliable, rapid and species-typical — a description the competing accounts also predict.