Tag Archives: development

The Development of Speech and Conversation (Age 0-5)


Communication at any age requires a skill set including the obvious such as a proper vocabulary and grammatical accuracy. For a child, a conversation is far more difficult because vocabulary and grammar are not the only things that are still developing. The five years leading up to this communicative breakthrough also depends on the phonological and social development of the child.

Component 1: Phonological Development 

Firstly, the quintessential ingredient to verbal speech of any kind is phonological development. When infants are born they all have the ability to perceive the sounds and tones used in all languages. Experience with their own language over the first year of their life, slowly allows them to tune into the phonemic contrasts between their own language over others (Smith et al. 2011). For example, when a Japanese baby is 8 months old, they can distinguish /r/ and /l/ sounds; however, by the time they are one, they no longer can (Purves, 2001).

This may not seem like a useful skill; however, it is necessary for an infant to become an expert at their own mothertongue. Adults play a quintessential role by building on the biological rhythm of their babies developing speech. By 10 months, the canonical babbling comes to reflect the prosody of their surrounding language of their parents (De Boysson-Bardies, 1993). Clearly when infants are this young, it is essential for close proximity between caregiver and infant. Characteristics of contingent talk such as exaggerated facial expressions, repetition and eye-contact ensure optimal attention. Without this attention, the infant would not gain the benefits of contingent talk and their vocabulary acquisition would suffer.

Component 2: Acquisition of Vocabulary 

Hand in hand with phonological development is the acquisition of vocabulary. The first step of any child’s vocabulary acquisition is contingent talk. Contingent talk is when a caregivers ‘scaffolds’ learning by talking about what the infants is already attending to (Carpenter et al. 1998). Various forms exist including child-direct speech, following in, expansion and clarification and all of these forms help co-regulate intentions (Fogel, 1993). In other words, both the child and the caregiver work together to improve the language of the child. As the name suggests, scaffolding language allows the caregiver to just teach their child new words, but also to improve the quality of their word choice and the coherence between words.

Furthermore, contingent talk is instrumental in the development of theory of mind (Astington & Baird, 2005). In relation, understanding the intention of a caregiver also helps build in a child’s vocabulary. As a paradigm, when an experimenter tells an 18-month-old that they are looking for a ‘toma’ and then proceeds to look for it, rejecting objects until settling, with satisfaction for a final object, the majority of 18-month-olds will infer that this final object is the ‘toma’ (Tomaselo, 2003). Lastly, what all of these skills lead up to is the 100 word transition phase. After a child learns his or her first words, the next couple of months consistent of holophrases such as “nomore” until they have learnt about 100 words. Beyond this point, at around 18 months, children switch from holophrases to telegraphic speech (Bates et al. 1995). Three to four word phrases then begin around 24-27 months, the stage when grammar acquisition becomes important.

Component 3:Acquisition of Grammar 

Grammar becomes increasingly more important around 24 months because now word order actually begins to change the meaning of speech. The two major components of grammar are syntax and morphology. Syntax is the organisation of words into larger structure like sentence; who did what to whom. Understanding knowing who did what to whom or the agent-patient relationships is vital to communication. Around the age of three, children start to show understanding on this relationship. Tomasello et al. (1998; 1999) taught children made-up verbs and by age three, the children were able to act out appropriate actions and modify the agent-patient relationships to fit new scenes.

Once this skill has been attained, children can also start using synaptic bootstrapping; using grammatical information to infer the meaning of unfamiliar words (Gleitman, 1990). This is particularly useful when a child is having a conversation with anyone with a broader vocabulary, allowing them to carry on speaking without actually knowing every word. To continue, understanding morphology or word structure like plurals, possession, tense etc. allows children to use words productively in conversation. The wug test (Berko, 1958), suggests that understanding morphemes develops between the age of four and five. Understanding both syntax and morphology helps a five year old get around the barriers of having a conversation with someone more versed than them.

Component 4: Developing Pragmatics 

Finally, the acquisition of pragmatics is also a necessary tool for holding a conversation, regardless of age. The first pragmatic skills occurs even in infants, maintaining eye-contact with the people speaking to them. Maintaining eye-contact and eventually responding with smiles and sounds lets the other speaker know that the child is paying attention. Eventually, around 11 months this skill helps develop joint attention whereby the child can actually direct their caregivers attention (Smith et al. 2011). By a child is five, expressing intent is necessary to get their point across, setting the topic and for taking turns in speaking (Bates, 1976; Strivers et al. 2009). Finally, developing an understanding for implicature and referencing is also a necessary skill for conversation. Studies show that by age five children have learnt that they can use pronouns to refer to people, persons and things which are clearly seen or recently spoken off (Matthews et al. 2006). Until this age, to refer to things children will point to remain ambiguous. Understanding implicature like “I ate some cake” meaning “some” and not “all” also develops by around five years of age. Both of these skills are extremely helpful tools for a five year especially for clear communication and reduces ambiguity and confusion. Fortunately, by this age, should ambiguity remain, a five-year old will actively search the scene for clues that will reduce confusion. In other words, by age five, children have learnt the pragmatic skills to steer them through must conversational confusion.


Astington, J. W., & Baird, J. A. (2005). Why language matters for theory
of mind. Oxford, England: Oxford University Press.

Bates, E. (1976). Language and context: Studies in the acquisition of pragmatics. New York: Academic Press.

Berko, J. (1958). The child’s learning of English morphology (Doctoral dissertation, Radcliffe College).

Carpenter, M., Akhtar, N., & Tomasello, M. (1998). Fourteen-through 18-month-old infants differentially imitate intentional and accidental actions. Infant Behavior and Development, 21(2), 315-330.

Caselli, M. C., Bates, E., Casadio, P., Fenson, J., Fenson, L., Sanderl, L., & Weir, J. (1995). A cross-linguistic study of early lexical development. Cognitive Development, 10(2), 159-199.

De Boysson-Bardies, B. (1993). Ontogeny of language-specific syllabic productions (pp. 353-363). Springer Netherlands.

Fogel, A. (1993). Developing through relationships. Chicago: University of Chicago Press.

Gleitman, L. (1990). Structural sources of verb learning. Language Acquisition, 1, 1-63.

Matthews, D., Lieven, E., Theakston, A., & Tomasello, M. (2006). The effect of perceptual availability and prior discourse on young children’s use of referring expressions. Applied Psycholinguistics, 27(03), 403-422.

Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A. S., McNamara, J. O., & Williams, S. M. (2001). The Development of Language: A Critical Period in Humans.

Smith, P., & Cowie, H. (2011). Understanding children’s development (5th ed.). Chichester, West Sussex: Wiley.

Stivers, T., Enfield, N. J., Brown, P., Englert, C., Hayashi, M., Heinemann, T., Levinson, S. (2009). Universals and cultural variation in turn-taking in conversation. Proceedings of the National Academy of Sciences, 106(26)

Tomasello M. 1998. Reference: intending that others jointly attend. Pragmat. Cogn. 6:219–34

Tomasello M. 1999. Perceiving intentions and learning words in the second year of life. See Bowerman & Levinson 1999. In press

Tomasello, M. (Ed.). (2003). The new psychology of language: Cognitive and functional approaches to language structure (Vol. 2). Psychology Press.

Basic Nutrition: Essential Nutrients and Biosynthesis

Our bodies rely on food for energy but also for biosynthesis. Biosynthesis is the production of complex molecules within living organisms or cells; a process necessary for self-maintenance. For example, the synthesis of protein from neuropeptides. Two necessary precursors for biosynthesis are organic carbon (such as from sugar) and organic nitrogen (such as from amino acids). For a diet to be sufficient, therefore, it must supply chemical energy, organic molecules and finally essential nutrients.

For energy, animals ingest and digest nutrients such as carbohydrates, proteins and lipids to get enough ATP necessary for cellular respiration and energy storage. Essential nutrients are ingested as precursors to complex molecules and as minerals and vitamins. Unlike complex molecules, essential nutrients cannot be synthesised from raw materials. Thus, they must be ingested.

Amino Acids and Fatty Acids

Four types of essential nutrients exist: amino acids, fatty acids, vitamins and minerals. Approximately, half of the 20 amino acids are required for humans including: methionine, valine, threonine, phenylaline, leucine, isoleucine, tryptophan, lysine and histidine. Meat, fish, poultry, dairy products are considered complete proteins because they contain all essential amino acids. However, vegans and vegetarians or even meat-eaters can get all their essential amino acids by eating a full diet consisting of beans, legumes, nuts, seeds and vegetables. Insufficient amounts of amino acids causes protein deficiency, which can be severely detrimental to healthy development. Therefore, if you stop eating meat, it is important to make sure you are eating a diet that contains all your essential amino acids.


Essential fatty acids are also required. Only two are known to be essential for human survival: alpha-linoleic acid and linoleic acid. Alpha-linoleic acid is a long-chain omega-3 fatty acid and is high in food such as salmon, tofu, shrimp, flax seeds and walnuts (fish, seeds, grains and vegetables). Linoleic acid is a long-chain omega-6 fatty acid and is found nuts, grains, cereals and poultry. Insufficient amounts of omega-3 and omega-6 contributes to impaired cellular functioning and heart disease.

Vitamins and Minerals 

The final two essential nutrients are vitamins and minerals. Vitamins come in two, organic forms: soluble and water-soluble. Fat-soluble vitamins are found in fatty foods such as animal products, vegetable oils, etc. They include vitamin A, D, E and K and are stored in our liver and fatty tissue. Deficiency in certain vitamins cause different issues (a future post will discuss this in more detail). Water-soluble vitamins, on the other hand, are not stored in the body and so need to be consumed more frequently. These means that when we urinate, these vitamins leave our body. Fortunately, that means it is hard to consume too many water-soluble vitamins. Too many fat-soluble vitamins can cause toxicity. Water-soluble vitamins include vitamin C, B and folic acid and can be found in foods such as fruit, vegetables (especially greens) and grains. As water-soluble vitamins are sensitive to heat and air, boiling can destroy the vitamins. Foods high in fat-soluble vitamins are far more durable.

Minerals on the other hand are inorganic and include calcium, iron, phosphorus, magnesium, sulphur, sodium, potassium and chloride. Minerals also come in two forms: macro or major minerals and trace elements. Macrominerals include electrolytes and the body stores about 5 grams of each one on hand. In order to stay healthy, a person to consume about 100mg a day to maintain the 5 gram store and equalise the loss. Trace elements are found in much smaller quantities, hence their name and include iron, zinc, iodine, selenium, copper, manganese, fluoride, chromium and molybdenum. Minerals are essential because they serve as reinforcers for bone growth, strong teeth, maintaining homeostasis and synthesising energy from food. A great source of minerals is from plants such as fruits, vegetables and nuts as they get minerals directly from the soil they grow in. Grains, meats, cereals, dairy, etc. also contain minerals but in a diluted amount due to processing or because they have already been used by the animal itself.

All in all, a proper diet needs to incorporate all essential nutrients for proper health and functioning.


Campbell, N. A., & Reece, J. B. (2008). Animal Nutrition . Biology (8th ed., ). San Francisco: Pearson, Benjamin Cummings.

Rinzler, C. A. (2006). Nutrition for Dummies (4th ed.). Indianapolis, IN: Wiley Pub.

Vitamins and minerals . (2012, November 26). . Retrieved June 24, 2014, from http://www.nhs.uk/conditions/vitamins-minerals/Pages/vitamins-minerals.aspx