Language development

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.[4] 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".[5] Chomsky says that all children have what is called an innate language acquisition device (LAD). 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.[6] 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 (UG), which posits that a certain set of structural rules are innate to humans, independent of sensory experience.[7] 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 (see above). Rather than a LAD evolved specifically for language, empiricists believe that general brain processes are sufficient enough 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). 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.[8]

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.[9] Some empiricist theory accounts today use behaviorist models.[10]

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[11] and Vygotsky's social theories that attribute the development of language to an individual's social interactions and growth.[12]

Evolutionary biologists 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.

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 (LAD).[13] 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.[14]

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. It has also 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.[15][16] Further research has indicated the influence of the FOXP2 gene.[17]

Relationship between interpersonal communication and the stages of development. The greatest development of language occurs in the stage of infancy. As the child matures, the rate of language development decreases.

0-1 years of age:

An infant mainly uses non-verbal communication (mostly gestures) to communicate. For a newborn, crying is the only means of communication. Infants 1-5 months old have different tones of crying that indicate their emotions. Infants also begin laughing at this stage. At 6-7 months old, infants begin to respond to their own name, yell and squeal, and distinguish emotions based on the tone of voice of the mother and father. Between 7 and 10 months the infant starts putting words together, for example "mama" and "dada", but these words lack meaning and significance. Verbal communication begins at approximately 10-12 months, and the child starts to imitate any sounds they hear, for example animal sounds. The non-verbal communication of infants includes the use of gaze, head orientation and body positioning. Gestures are also widely used as an act of communication. All these stages can be delayed if the parents do not communicate with their infant on a daily basis.[18]

Nonverbal communication begins with the comprehension of parents and how they use it effectively in conversation. Infants are able to break down what adults and others are saying to them and use their comprehension of this communication to produce their own.[19]

1–2 years of age:

Verbal and nonverbal communication are both used at this stage of development. At 12 months, children start to repeat the words they hear. Adults, especially parents, are used as a point of reference for children in terms of the sound of words and what they mean in context of the conversation. Children learn much of their verbal communication through repetition and observing others. If parents do not speak to their children at this age it can become quite difficult for them to learn the essentials of conversation.[20] The vocabulary of a 1–2 year old should consist of 50 words and can be up to 500. Gestures that were used earlier on in development begin to be replaced by words and eventually are only used when needed. Verbal communication is chosen over nonverbal as development progresses.[21]

2–3 years of age:

Children aged 2–3 communicate best in a turn-taking style. This creates a conversational structure that makes it easier for verbal communication to develop. It also teaches patience, kindness, and respect as they learn from the direction of elders that one person should speak at a time. This creates interactional synchrony during their preverbal routines that shapes their interpersonal communication skills early on in their development.[22] Children during this stage in their life also go through a recognition and continuity phase. Children start to see that shared awareness is a factor in communication along with their development of symbolic direction of language. This especially affects the relationship between the child and the caregiver; it is a crucial part of self-discovery for the child when they begin to take ownership over their own actions in a continuous manner.[22]

3–5 years of age:

In this age group children are still learning how to form abstract thoughts and are still communicating concretely. Children begin to be fluent in connecting sounds, syllables, and linking words that make sense together in one thought. They begin to participate in short conversations with others. Stuttering can develop, generally resulting in slowed-down speech with a few letter enunciation errors (f, v, s, z).[23] At the beginning of this stage toddlers tend to be missing function words and misunderstand how to use verb tenses.Over time they start including functional words, pronouns, and auxiliary verbs.[24] This is the stage at which most children can pick up on emotional cues of the tone of adults' conversation. If negative feedback is distinguished by the child, this ends with fear and avoidance of the associated verbal and nonverbal cues. Toddlers develop the skills to listen and partially understand what another person is saying and can develop an appropriate response.

5–10 years of age:

Much language development during this time period takes place in a school setting. At the beginning of the school age years, a child’s vocabulary expands through exposure to reading, which also helps children to learn more difficult grammatical forms, including plurals and pronouns. They also begin to develop metalinguistic awareness which allows them to reflect and more clearly understand the language they use. They therefore start to understand jokes and riddles. Reading is a gateway for learning new vernacular and having confidence in complex word choices while talking with adults. This is an important developmental stage socially and physiologically for the child.[25] School-aged children can easily be influenced through communication and gestures.[23] As children continue to learn communication, they realize the difference between forms of intentions and understand that there are numerous different ways to express the same intent, with different meaning.[22]

10–18 years of age:

By the age of 10, the child's cognitive potential has matured and they can participate fully and understand the purpose of their conversations. During this time, the sophistication and effectiveness of communication skills increase and understanding of vocabulary and grammar increases as a result of education. Adolescents go through changes in social interactions and cognitive development that influence the way they communicate.[26] They often use colloquial speech (slang), however, which can increase confusion and misunderstandings.[23] An individual’s style of interpersonal communication depends on who they are communicating with. Their relationships change influencing how they communicate with others. During this period, adolescents tend to communicate less with their parents and more with their friends. When discussions are initiated in different channels of communication, attitude and predispositions are key factors that drive the individual to discuss their feelings. This also shows that respect in communication is a trait in interpersonal communication that is built on throughout development.[25] The end of this adolescent stage is the basis for communication in the adult stage.

Research in writing development has been limited in psychology.[36] In the research that has been conducted, focus has generally centred on the development of written and spoken language and their connection. Spoken and written skills could be considered linked. Researchers believe that children's spoken language influences their written language.[37] When a child learns to write they need to master letter formation, spelling, punctuation and they also have to gain an understanding of the structure and the organisational patterns involved in written language.[38]

Kroll's theory is one of the most significant on children's writing development. He proposed that children's writing development is split into 4 phases. Kroll explicitly states that these phases are 'artificial' in the sense that the boundaries between the phases are imprecise and he recognises that each child is different, thus their development is unique.[37] The phases of writing development have been highlighted to give the reader a broad outline of what phases a child goes through during writing development; however when studying an individual's development in depth, the phases may be disregarded to an extent.

The first of Kroll's phases is the preparation for writing phase. In this phase the child is believed to grasp the technical skills needed for writing, allowing them to create the letters needed to write the words the children say. In this initial phase children experience many opportunities to extend their spoken language skills. Speaking and writing are considered fairly separate processes here, as children's writing is less well developed at this stage, whereas their spoken language is becoming more skilled.[37]

Kroll considers the second phase in writing development to be consolidation. Here, children begin to consolidate spoken and written language. In this phase children's writing skills rely heavily on their spoken language skills, and their written and spoken language becoming integrated.[37] Children's written language skills become stronger as they use their spoken language skills to improve their writing. Then in turn, when a development in children's written language skills is seen, their spoken language skills have also improved. A child's written language in this phase mirrors their spoken language.[37]

In the third phase, differentiation, children begin to learn that written language regularly differs in structure and style from spoken language. The growth from consolidation to differentiation can be challenging for some children to grasp.[37] Children can 'struggle with the transformation from the basically overt language of speech to the essentially covert activity of writing'.[39] In this phase, the child learns that writing is generally considered more formal than spoken language, which is thought to be casual and conversational. Here, it is believed that children begin to understand that writing serves a purpose.[40]

Kroll considers the last phase to be the systematic integration phase. A differentiation and integration between the child's speaking and writing can be seen in this phase. This means that speaking and writing have 'well-articulated forms and functions';[40] however, they are also integrated in the sense that they use the same system. As a result of the individual being aware of the audience, context and reason they are communicating, both written and spoken language are able to overlap and take several forms at this stage.[40]

Kroll used the four phases to give an explanation and generalise about the development of these two aspects of language. The highest significance is placed on the second and third phase, consolidation and differentiation respectively.[40] It could be concluded that children's written and spoken language, in certain respects, become more similar to age, maturation, and experience; however, they are also increasingly different in other respects. The content of the skills are more similar, but the approach used for both writing and speaking are different.[40] When writing and speaking development is looked at more closely it can be seen that certain elements of written and spoken language are differentiating and other elements are integrating, all in the same phase.

Perera conducted a survey and her view mirrors that of Kroll to the extent that she used Kroll's four phases.[38] When a child undergoes initial learning of the written language, they have not yet fully mastered the oral language.[38] It is clear that their written language development is aided by their spoken language; it can also be said that their spoken language development is aided by the development of their written language skills. Kantor and Rubin believe that not all individuals successfully move into the final stage of integration.[41] Perera is also aware that it is hard to assign chronological ages to each phase of writing development, because each child is an individual, and also the phases are 'artificial'.

Other than Kroll's theory, there are four principles on early patterns in writing development discussed by Marie Clay in her book What Did I Write?. The four principles are recurring principle, the generative principle, the sign principle, and the inventory principle. The recurring principle involves patterns and shapes in English writing that develop throughout writing development. The generative principle incorporates the idea that a writer can create new meanings by organizing units of writing and letters of the alphabet. The sign principle is understanding that the word print also involves paper arrangement and word boundaries. And lastly, the inventory principle is the fact that children have the urge to list and name items that they are familiar with, and because of this they can practice their own writing skills.[42]

More recent research has also explored writing development. Myhill concentrated on the development of written language skills in adolescents aged 13 to 15.[43] Myhill discovered that the more mature writer was aware of the shaping of text, and used non-finite clauses, which mirrored Perera's results (1984).[43] Other researchers focused on writing development up until late adolescence, as there has been a limited research in this area.[36] Chrisite and Derewianke recognize that the survey conducted by Perera (1984) is still one of the most significant research studies in the writing development field and believe Perera's study is similar to theirs. Chrisite and Derewianke (2010) again propose four phases of writing development. The researchers believe that the process of writing development does not stop when an individual leaves formal education, and again, the researchers highlight that these phases are flexible in their onset. The first phase focuses on spoken language as the main aid for writing development, and the development then takes its course reaching the fourth phase, which continues beyond formal education.[36]

The environment a child develops in has influences on language development. The environment provides language input for the child to process. Speech by adults to children help provide the child with correct language usage repetitively.[44] Environmental influences on language development are explored in the tradition of social interactionist theory by such researchers as Jerome Bruner, Alison Gopnik, Andrew Meltzoff, Anat Ninio, Roy Pea, Catherine Snow, Ernest Moerk and Michael Tomasello. Jerome Bruner who laid the foundations of this approach in the 1970s, emphasized that adult "scaffolding" of the child's attempts to master linguistic communication is an important factor in the developmental process.

One component of the young child's linguistic environment is child-directed speech (also known as baby talk or motherese), which is language spoken in a higher pitch than normal with simple words and sentences. Although the importance of its role in developing language has been debated, many linguists think that it may aid in capturing the infant's attention and maintaining communication.[45] When children begin to communicate with adults, this motherese speech allows the child the ability to discern the patterns in language and to experiment with language.

Throughout existing research, it is concluded that children exposed to extensive vocabulary and complex grammatical structures more quickly develop language and also have a more accurate syntax than children raised in environments without complex grammar exposed to them.[46] With motherese, the mother talks to the child and responds back to the child, whether it be a babble the child made or a short sentence. While doing this, the adult prompts the child to continue communicating, which may help a child develop language sooner than children raised in environments where communication is not fostered.[47]

Child-directed speech concentrates on small core vocabulary, here and now topics, exaggerated facial expressions and gestures, frequent questioning, para-linguistic changes, and verbal rituals.[48] An infant is least likely to produce vocalizations when changed, fed, or rocked. The infant is more likely to produce vocalizations in response to a nonverbal behavior such as touching or smiling.

Child-directed speech also catches the child's attention, and in situations where words for new objects are being expressed to the child, this form of speech may help the child recognize the speech cues and the new information provided.[47] Data shows that children raised in highly verbal families had higher language scores than those children raised in low verbal families. Continuously hearing complicated sentences throughout language development increases the child's ability to understand these sentences and then to use complicated sentences as they develop. Studies have shown that students enrolled in high language classrooms have two times the growth in complex sentences usage than students in classrooms where teachers do not frequently use complex sentences.

Adults use strategies other than child-directed speech like recasting, expanding, and labeling:

• Recasting is rephrasing something the child has said, perhaps turning it into a question or restating the child's immature utterance in the form of a fully grammatical sentence. For example, a child saying "cookie now" a parent may respond with "Would you like a cookie now?"[49]
• Expanding is restating, in a linguistically sophisticated form, what a child has said. For example, a child may say "car move road" and the parent may respond "A car drives on the road."[44]
• Labeling is identifying the names of objects.[13] If a child points to an object such as a couch the mother may say "couch" in response. Labeling can also be characterized as referencing.[48]

Some language development experts have characterized child directed speech in stages. Primarily, the parents use repetition and also variation to maintain the infant's attention. Secondly, the parent simplifies speech to help in language learning. Third, any speech modifications maintain the responsiveness of the child. These modifications develop into a conversation that provides context for the development.[48]

It is crucial that children are allowed to socially interact with other people who can vocalize and respond to questions. For language acquisition to develop successfully, children must be in an environment that allows them to communicate socially in that language. Children who have learnt sound, meaning and grammatical system of language that can produce clear sentence may still not have the ability to use language effectively in various social circumstance. Social interaction is the footing stone of language.[52]

There are a few different theories as to why and how children develop language. One popular, yet heavily debated explanation is that language is acquired through imitation. This theory has been challenged by Lester Butler, who argues that children do not use the grammar that an adult would use. Furthermore, "children's language is highly resistant to alteration by adult intervention", meaning that children do not use the corrections given to them by an adult.[53] R.L Trask also argues in his book Language: The Basics that deaf children acquire, develop and learn sign language in the same way hearing children do, so if a deaf child's parents are fluent sign speakers, and communicate with the baby through sign language, the baby will learn fluent sign language. And if a child's parents aren't fluent, the child will still learn to speak fluent sign language. Trask's theory therefore is that children learn language by acquiring and experimenting with grammatical patterns, the statistical language acquisition theory.[54]

The two most accepted theories in language development are psychological and functional.

Psychological explanations focus on the mental processes involved in childhood language learning. Functional explanations look at the social processes involved in learning the first language.

• Phonology involves the rules about the structure and sequence of speech sounds.
• Semantics consists of vocabulary and how concepts are expressed through words.
• Grammar involves two parts.

• The first, syntax, is the rules in which words are arranged into sentences.
• The second, morphology, is the use of grammatical markers (indicating tense, active or passive voice etc.).

• Pragmatics involves the rules for appropriate and effective communication. Pragmatics involves three skills:
  • using language for greeting, demanding etc.,
  • changing language for talking differently depending on who it is you are talking to;
  • following rules such as turn taking, staying on topic.

Each component has its own appropriate developmental periods.

A language disorder is the impaired comprehension and or use of a spoken, written, and/or other symbol system. A disorder may involve problems in the following areas:

1. The form of language i.e. phonology, morphology, or syntax
2. The content i.e. semantics
3. The function of language in communication i.e. pragmatics

Olswang and colleagues have identified a series of behaviors in children in the 18–36 month range that are predictors for the need of language intervention.[76]

These predictors include:

• A smaller than average vocabulary
• A language comprehension delay of 6 months or a comprehension deficit with a large comprehension production gap
• Phonological problems such as restricted babbling or limited vocalizations
• Few spontaneous vocal imitations and reliance on direct modeling in imitation tasks
• Little combinatorial or symbolic play
• Few communicative or symbolic gestures
• Behavior problems[76]

Some of the many conditions that cause language development problems include:

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• Language Development in Children Checklist (3YRS)

• Social Language Use (Pragmatics) – American Speech-Language-Hearing Association (ASHA)
• Speech and Language Developmental Milestones, Your baby's hearing and communicative development checklist