Audio recordings of language programs—streaming—have an advantage over print or academic classes because hearing is how humans learn to speak. That is how we learned our native tongues, and how we effectively learn second languages. As babies, we listened to our parents speaking. In our hard-wired desire to communicate, we learned our native language by imitating them. According to linguists, babies begin by distinguishing basic syllables, and around 3 months, start to babble, making simple sounds (“ba-ba-ba” or “ma-ma-ma”). They also imitate the tonal changes of their parents’ language. By sixmonths, they can distinguish the sounds of their native language fromthose of foreign languages and begin to practice its sounds, intonations, and rhythms.Most children by the age of 1 year can say a few simple words, even if they aren’t clear on theirmeanings. At 18months, most children have a speaking vocabulary of eight to ten words. By 2, they begin forming simple sentences. And then language fluency begins to soar. In the early 1900s, European linguists proposed that language learning would be better if it were conducted in the target language. In this approach—called the Direct Method (or Natural Method)—all directions, explanations, and definitions are given in the language being taught. In a French class, French and only French is spoken or read. All grammar is learned inductively. While this method most closely imitates the way we learn our first language, it is difficult to teach and can be frustrating and discouraging to learners. Most audio-based language learning programs combine both native and target languages into talking phrasebooks.

Nativist theories hold that children are born with an innate propensity for language acquisition, and that this ability makes the task of learning a first language easier than it would otherwise be. These "hidden assumptions" allow children to quickly figure out what is and isn't possible in the grammar of their native language, and allow them to master that grammar by the age of three. Nativists view language as a fundamental part of the human genome, as the trait that makes humans human, and its acquisition as a natural part of maturation, no different from dolphins learning to swim or songbirds learning to sing. Chomsky originally theorized that children were born with a hard-wired language acquisition device (LAD) in their brains . He later expanded this idea into that of Universal Grammar, a set of innate principles and adjustable parameters that are common to all human languages. According to Chomsky, the presence of Universal Grammar in the brains of children allow them to deduce the structure of their native languages from "mere exposure". Much of the evidence supporting the nativist position is based on the early age at which children show competency in their native grammars, as well as the ways in which they do (and do not) make errors. Infants are born able to distinguish between phonemes in minimal pairs, distinguishing between bah and pah, for example. Young children (under the age of three) do not speak in fully formed sentences, instead saying things like 'want cookie' or 'my coat.' They do not, however, say things like 'want my' or 'I cookie,' statements that would break the syntactic structure of the Phrase, a component of universal grammar.Children also seem remarkably immune from error correction by adults, which Nativists say would not be the case if children were learning from their parents.