RETRIEVAL PRACTICE Take a moment to answer each of these Learning Objective Questions (repeated here from within this section). Then click the 'show answer' button to check your answers. Research suggests that trying to answer these questions on your own will improve your long-term retention (McDaniel et al., 2009).

Phonemes are a language’s basic units of sound. Morphemes are the elementary units of meaning. Grammar—the system of rules that enables us to communicate—includes semantics (rules for deriving meaning) and syntax (rules for ordering words into sentences).

Language development’s timing varies, but all children follow the same sequence. Receptive language (the ability to understand what is said to or about you) develops before productive language (the ability to produce words). At about 4 months of age, infants babble, making sounds found in languages from all over the world. By about 10 months, their babbling contains only the sounds found in their household language. Around 12 months of age, children begin to speak in single words. This one-word stage evolves into two-word (telegraphic) utterances before their second birthday, after which they begin speaking in full sentences.
     Linguist Noam Chomsky has proposed that all human languages share a universal grammar—the basic building blocks of language—and that humans are born with a predisposition to learn language. We acquire a specific language through learning as our biology and experience interact. Childhood is a critical period for learning to speak and/or sign fluently. This is an important consideration for parents of deaf children, who might master oral communication if given a cochlear implant during this critical period. Deaf culture advocates oppose such implants on the grounds that deafness is a difference, not a disability.

Aphasia is an impairment of language, usually caused by left-hemisphere damage. Two important language- and speech-processing areas are Broca’s area, a region of the frontal lobe that controls language expression, and Wernicke’s area, a region in the left temporal lobe that controls language reception. Language processing is spread across other brain areas as well, where different neural networks handle specific linguistic subtasks.

A number of chimpanzees and bonobos have (1) learned to communicate with humans by signing or by pushing buttons wired to a computer, (2) developed vocabularies of nearly 400 words, (3) communicated by stringing these words together, (4) taught their skills to younger animals, and (5) demonstrated some understanding of syntax. But only humans communicate in complex sentences. Nevertheless, other animals’ impressive abilities to think and communicate challenge humans to consider what this means about the moral rights of other species.

Although Benjamin Lee Whorf’s linguistic determinism hypothesis suggested that language determines thought, it is in fact more accurate to say that language influences thought. Different languages embody different ways of thinking, and immersion in bilingual education can enhance thinking. We often think in images when we use implicit (nondeclarative, procedural) memory—our automatic memory system for motor and cognitive skills and classically conditioned associations. Thinking in images can increase our skills when we mentally practice upcoming events.