Language development
Language development in humans is a process which starts early in life. Infants start without knowing a language, yet by 10 months, babies can distinguish speech sounds and engage in babbling. Some research has shown that the earliest learning begins in utero when the fetus starts to recognize the sounds and speech patterns of its mother's voice and differentiate them from other sounds after birth.
Typically, children develop receptive language abilities before their verbal or expressive language develops. Receptive language is the internal processing and understanding of language. As receptive language continues to increase, expressive language begins to slowly develop.
Usually, productive/expressive language is considered to begin with a stage of pre-verbal communication in which infants use gestures and vocalizations to make their intents known to others. According to a general principle of development, new forms then take over old functions, so that children learn words to express the same communicative functions they had already expressed by proverbial means.
Children learn syntax through imitation, instruction, and reinforcement.
Theoretical frameworks
Language development is thought to proceed by ordinary processes of learning in which children acquire the forms, meanings, and uses of words and utterances from the linguistic input. Children often begin reproducing the words that they are repetitively exposed to. The method in which we develop language skills is universal; however, the major debate is how the rules of syntax are acquired. There are two quite separate major theories of syntactic development: an empiricist account by which children learn all syntactic rules from the linguistic input, and a nativist approach by which some principles of syntax are innate and are transmitted through the human genome.The nativist theory, proposed by Noam Chomsky, argues that language is a unique human accomplishment, and can be attributed to either "millions of years of evolution" or to "principles of neural organization that may be even more deeply grounded in physical law". Chomsky says that all children have what is called an innate language acquisition device. Theoretically, the LAD is an area of the brain that has a set of universal syntactic rules for all languages. This device provides children with the ability to make sense of knowledge and construct novel sentences with minimal external input and little experience. Chomsky's claim is based upon the view that what children hear—their linguistic input—is insufficient to explain how they come to learn language. He argues that linguistic input from the environment is limited and full of errors. Therefore, nativists assume that it is impossible for children to learn linguistic information solely from their environment. However, because children possess this LAD, they are in fact, able to learn language despite incomplete information from their environment. Their capacity to learn language is also attributed to the theory of universal grammar, which posits that a certain set of structural rules are innate to humans, independent of sensory experience. This view has dominated linguistic theory for over fifty years and remains highly influential, as witnessed by the number of articles in journals and books.
The empiricist theory suggests, contra Chomsky, that there is enough information in the linguistic input children receive and therefore, there is no need to assume an innate language acquisition device exists. Rather than a LAD evolved specifically for language, empiricists believe that general brain processes are sufficient for language acquisition. During this process, it is necessary for the child to actively engage with their environment. For a child to learn language, the parent or caregiver adopts a particular way of appropriately communicating with the child; this is known as child-directed speech. CDS is used so that children are given the necessary linguistic information needed for their language. Empiricism is a general approach and sometimes goes along with the interactionist approach. Statistical language acquisition, which falls under empiricist theory, suggests that infants acquire language by means of pattern perception.
Other researchers embrace an interactionist perspective, consisting of social-interactionist theories of language development. In such approaches, children learn language in the interactive and communicative context, learning language forms for meaningful moves of communication. These theories focus mainly on the caregiver's attitudes and attentiveness to their children in order to promote productive language habits.
An older empiricist theory, the behaviorist theory proposed by B. F. Skinner suggested that language is learned through operant conditioning, namely, by imitation of stimuli and by reinforcement of correct responses. This perspective has not been widely accepted at any time, but by some accounts, is experiencing a resurgence. New studies use this theory now to treat individuals diagnosed with autism spectrum disorders. Additionally, relational frame theory is growing from the behaviorist theory, which is important for acceptance and commitment therapy. Some empiricist theory accounts today use behaviorist models.
Other relevant theories about language development include Piaget's theory of cognitive development, which considers the development of language as a continuation of general cognitive development and Vygotsky's social theories that attribute the development of language to an individual's social interactions and growth.
Biological preconditions
are skeptical of the claim that syntactic knowledge is transmitted in the human genome. However, many researchers claim that the ability to acquire such a complicated system is unique to the human species. Non-biologists also tend to believe that our ability to learn spoken language may have been developed through the evolutionary process and that the foundation for language may be passed down genetically. The ability to speak and understand human language requires speech production skills and abilities as well as multisensory integration of sensory processing abilities.Scientists have conducted extensive research to see if other animal species are capable of learning a complex human language. Several studies have worked with great apes, owing to their close evolutionary relationship to humans. In the documentary Project Nim, for example, researcher Herbert S. Terrace conducted the study to nurture a young chimpanzee with intimate human interaction. The researchers trained the chimp American Sign Language and treated it like a human child. Finally, the chimp was able to learn over 114 signs to communicate his wants to the caregivers. Unlike humans, however, Nim was unable to make use of significant grammar or context. Other attempts to teach great apes language have met with varying degrees of success, and whether the communication the apes achieve can be equated to human language is controversial.
One hotly debated issue is whether the biological contribution includes capacities specific to language acquisition, often referred to as universal grammar. For fifty years, linguist Noam Chomsky has argued for the hypothesis that children have innate, language-specific abilities that facilitate and constrain language learning. In particular, he has proposed that humans are biologically prewired to learn language at a certain time and in a certain way, arguing that children are born with a language acquisition device. However, since he developed the minimalist program, his latest version of theory of syntactic structure, Chomsky has reduced the elements of universal grammar, which he believes are prewired in humans to just the principle of recursion, thus voiding most of the nativist endeavor.
Researchers who believe that grammar is learned rather than innate, have hypothesized that language learning results from general cognitive abilities and the interaction between learners and their human interactants. Based on studies of the developing visual system by Torsten Wiesel and David Hubel, it has been suggested that the environment guides the development of language networks in the brain by selecting the neurons and their synapses that are most active during the prolonged early development of humans in a socio-linguistic environment. According to this theory, the neural substrate for language results from a combination of the genetically determined complexity of the human brain and the 'functional validation of synapses' during the long period of postnatal maturation that is unique among primates. Similarly, it has recently been suggested that the relatively slow development of the prefrontal cortex in humans may be one reason that humans are able to learn language, whereas other species are not. Further research has indicated the influence of the FOXP2 gene.
Stages
0–1 years of age:1–2 years of age:
2–3 years of age:
3–5 years of age:
5–10 years of age:
''10–18 years of age:''
Gender differences
Children versus adults
Language development and processing begins before birth. Evidence has shown that there is language development occurring antepartum. DeCasper and Spence performed a study in 1986 by having mothers read aloud during the last few weeks of pregnancy. When the infants were born, they were then tested. They were read aloud a story while sucking on a pacifier; the story was either the story read by the mother when the infant was in utero or a new story. The pacifier used was able to determine the rate of sucking that the infant was performing. When the story that the mother had read before was heard, the sucking of the pacifier was modified. This did not occur during the story that the infant had not heard before. The results for this experiment had shown that the infants were able to recognize what they had heard in utero, providing insight that language development had been occurring in the last six weeks of pregnancy.Throughout the first year of life, infants are unable to communicate with language. Instead, infants communicate with gestures. This phenomenon is known as prelinguistic gestures, which are nonverbal ways that infants communicate that also had a plan backed with the gesture. Examples of these could be pointing at an object, tugging on the shirt of a parent to get the parent's attention, etc. Harding, 1983, devised the major criteria that come along with the behavior of prelinguistic gestures and their intent to communicate. There are three major criteria that go along with a prelinguistic gesture: waiting, persistence, and ultimately, development of alternative plans. This process usually occurs around 8 months of age, where an appropriate scenario may be of a child tugging on the shirt of a parent to wait for the attention of the parent who would then notice the infant, which causes the infant to point to something they desire. This would describe the first two criteria. The development of alternative plans may arise if the parent does not acknowledge what the infant wants, the infant may entertain itself to satisfy the previous desire. The way the parent responds to their child in this situation of "needing" and "wanting" will also result in the kind of attachment style their child will have.
When children reach about 15–18 months of age, language acquisition flourishes. There is a surge in word production resulting from the growth of the cortex. Infants begin to learn the words that form a sentence and within the sentence, the word endings can be interpreted. Elissa Newport and colleagues found that humans learn first about the sounds of a language, and then move on to how to speak the language. This shows how infants learn the end of a word and know that a new word is being spoken. From this step, infants are then able to determine the structure of a language and word.
It appears that during the early years of language development females exhibit an advantage over males of the same age. When infants between the age of 16 and 22 months were observed interacting with their mothers, a female advantage was obvious. The females in this age range showed more spontaneous speech production than the males and this finding was not due to mothers speaking more with daughters than sons. In addition, boys between 2 and 6 years as a group did not show higher performance in language development over their girl counterparts on experimental assessments. In studies using adult populations, 18 and over, it seems that the female advantage may be task dependent. Depending on the task provided, a female advantage may or may not be present. Similarly, one study found that out of the 5.5% of American children with language impairments, 7.2% are male, and 3.8% are female. There are many different suggested explanations for this gender gap in language impairment prevalence.