Developmental Milestones [Part 2: Toddlers]

Published: 13 Jan 2022

Developmental Milestones [Part 1: Infancy]


A toddler is a person who “totters” according to history books. The interesting thing about tottering (or toddling) is that, in the early 1800’s, it would typically apply to the elderly as well as occasionally being used in reference to the young. It wasn’t until the early-mid 1900’s that we began using the term “toddler” for our little ones. 

The common term for young children, prior to Arnold Gessell’s popularising of “toddler”, was run-about. Having raised six daughters through this stage of life, I feel that run-about is the more accurate descriptor. They didn’t toddle and totter for long, but they developed run-about capability that has kept me on my toes ever since!

(As an interesting aside, Gessell, the Yale psychologist who created our timelines and benchmarks for development, was also the person who invented the idea that there are terrible twos after he realised how impossible it was to negotiate with them midway through their third year of life. Does it make you feel better that the guy who created this idea of milestones and timelines struggled with kids as much as you and I? Note. He didn’t actually coin the phrase “terrible twos” but he did say that two and a half is “the most exasperating age in the preschool period”.) 

Finally, before we talk about the developmental stage that is recognised today as toddlerhood, it’s worth noting that very few languages throughout the world have a word for toddler or preschooler. The French word for toddler, for example, is bambin which can apply to a child aged anywhere from two through to ten. 

Nevertheless, in Western society we talk of toddlers as those children aged from around one-year-old to around three. And there is a lot going on in their bodies and brains that we need to discuss.

This incredible development transforms the fabric of our child’s life. Language allows them to articulate their thoughts, develop social relationships, and express themselves emotionally. They learn that the world is theirs to navigate and negotiate. 

We experience an era of explosive independence as our toddler starts saying “No” to everything (which I’m quite certain they learn from us saying “No” to everything). And with increased mobility, we find ourselves running faster than we have in years to catch them before they run on the road, attack their sibling, taunt the cat or just because to them running away is just so funny! Welcome to toddlerhood.


During infancy and toddlerhood about one million new brain cells develop every second in our child’s brain and those connections continue to proliferate. This happens because so much of what they encounter in their environment is new, or is only just beginning to make sense. One of the most powerful ingredients in this developmental process is the “serve and return” relationship between children and their parents. This is the interaction that happens when they make a sound and we respond. Maybe they “goo” and we repeat the sound. Perhaps we sing a tune and they mimic us. Serve and return is vital in healthy development for our children and in creating secure attachments that build wellbeing and relationships throughout our child’s life. (At the extreme alternative end, children who miss the attuned serve and return, but instead experience high stress, abuse, or neglect will find this is toxic to the developing brain ). 


Language development explodes during this phase. From the age of one to two years our children start to pick up and use lots of words, generally one at a time and on repeat. Mum. Dad. Dog. You’ll notice your toddler overgeneralise, with every four-legged animal being a dog, or every human that’s not mum being dad. 

At around 15 months, your child will point to things and ask you to name them. She’ll try to repeat them, often with very funny results. By 18 months, your child will know and use around 20-100 meaningful words. A word eruption is about to occur, with new words being added to their vocabulary daily.

At around two years, your child will start putting words together in what we call “telegraphic speech”. As an example, ‘daddy gone work’ or ‘me go’. They’ll use only a few descriptive words at this age – for example, ‘big’ or ‘red’. Their word combinations will consist mainly of nouns and some verbs (‘dog eat’, ‘car go’). Pronunciation will likely be wrong as they haven’t yet learned how to make the right shapes with their mouths. “Cat” will be “tat”, for example.

The way we instinctively speak to babies -- higher pitch, slower speed, exaggerated pronunciation -- not only appeals to them, but likely helps them learn to understand what we're saying. This speech is called “Motherese”, or the more politically correct “Parentese”. New research from the University of Florida suggests that this kind of talk can help babies learn to produce their own speech. By mimicking the sound of a smaller vocal tract, the researchers think, we're cluing babies in to how the words should sound coming out of their own mouths. In the study, the researchers changed the frequency sounds to mimic either an infant or adult vocal tract, and then tested how infants reacted. Six- to eight-month-old babies "displayed a robust and distinct preference for speech with resonances specifying a vocal tract that is similar in size and length to their own," they wrote. The effect wasn’t found for four-month-old babies, suggesting that the brain responds when it’s ready for speech and language, rather than on our timetable.

Emotional regulation

While emotion regulation in infancy only exists by reflex (like sucking a fist), toddlers understand that parents can help them regulate their emotions. The central challenge for toddlers, according to several studies , is fear. Everything is new. Everything is big. Everything makes no sense. The world can be a scary place when you’re 80cm tall and weigh 15kgs. A secondary emotion is anger when being told “no”. Each can lead to explosive outbursts

With regulation capacity still close to zero, parents can begin developing their child’s emotional intelligence by talking to them about emotions and encouraging them to name. 

The best strategies for helping? 

Distraction, or selecting (or modifying) situations where toddlers will be so that things aren’t overwhelming and frightening for them. Naming emotions also helps toddlers learn that emotions are normal. “He sure looks angry.” “Why do you think he looks so sad?” These observations provide opportunities for toddlers to learn about emotions and develop an understanding of how to navigate them. Toddlers also learn about managing their emotions by watching the way we manage ours.

Self awareness & emotion

When they are born, our babies have no idea that they are an individual person. They think that they are part of us. (Well, they don’t really think very much at all. They just have reflexes.) As they move, touch, and explore, they begin to realise they have agency, but it’s not until age 2 that they realise they’re an individual.

It starts slowly as they move, touch and explore. At around 18 months, your child will refer to themselves by name. A few months later, they’ll begin to understand and use ‘I’ to refer to themselves. This is when they start to realise they’re a separate person with their own ideas. It’s about this age (24 months) that they begin to recognise themselves in the mirror. 

The appearance of emotions such as embarrassment, pride, guilt and shame also demonstrates that a child is developing self-consciousness. Parents may notice that by the time they are three-years-old, their child shows embarrassment or shame (or pride). And she is motivated to make amends for wrongdoing, or hides when unhappy about something they have done. They become more self-referential, complaining that “I hungry” or “I want…”

Behaviour regulation

Our society has developed a parenting approach that is based on adult’s wants rather than children’s needs. This means that when a child who has limited brain power, limited perspective on what others want or how life should be (according to the parent), limited emotional regulation capacity, and limited speech capability doesn’t get what they want, emotions explode and behaviour follows. 

While this is inconvenient, it’s normal. And the best way to navigate this period is with patience and a willingness to work through things slowly. If we can adapt to being responsive to our children’s needs, emotions and behaviours, those big emotions and behaviours will be more moderate. This does not mean we give in to all of our children’s demands though as indulgence does not satisfy needs. Meeting their needs means focusing on their emotional world and providing them with the security and emotional safety/understanding they need. It’s about responding with involvement, developing suitable structure around them, and providing autonomy where possible.

Milestones from age 1-ish to age 3 (summary)

Physical and motor skill
  • Toddlers are running, they can walk backwards, and they love to climb. They are also old enough to jump with both feet (usually into a puddle).
  • A 2 year-old can turn a book’s pages, throw a ball, and stack blocks or play with Lego.
  • By around the age of two, a toddler knows they’re in trouble, has BIG emotions, and feels embarrassment. This means they have a sense of conscience, a sense of self, and the capacity to begin to act autonomously.
  • A child learns, by around age 2, that we can pretend - and they love pretend games (like when Dad pretends to be a big lion that will eat them up).
  • They understand “object permanence” - that something can disappear but still exist (like mum leaving the room but coming back, or a doll being lost but being able to be found). 
  • By 18-24 months, our children are expanding their vocabulary rapidly. They use telegraphic speech (two-word sentences), over-generalisation (every animal is a dog), and over-extension (I jumpeded on Mummy!) to communicate.
Social development
  • Children want to be close to those at the top of their attachment hierarchy. They love their mum, their dad, their grandparents, their siblings, and those with whom they’re most familiar. And they often do NOT like strangers.
  • They like to be near same-age peers, but typically play in parallel rather than together. 
  • They don’t like sharing.
  • Non-compliance becomes the norm for parents of toddlers. Their favourite word is no. But only when they say it - not when you say it. 
  • But a child’s personality is still barely forming.

What you can do for your toddler

Toddlers will develop in healthy ways when parents:

  • Play games and do puzzles, 
  • Read. Lots. 
  • Speak to your child constantly, naming and describing everything in their world. “This is a pink pig eating green grass. And here’s the white horse. It’s a big horse isn’t it?” 
  • When they tell you they want to go in the “tar”, smile and respond, “Going in the car is fun isn’t it.” 
  • If your child points, encourage them to use the correct word (but don’t say “use your words”). 
  • If they want the doll but can’t say it, guide them through it. “You want this? The d… d... do.. doll”. 

Towards the end of this toddler period you can also play matching games and counting games. Play with blocks, do art projects, get them developing their fine motor skills. And play with balls to develop gross motor skills and coordination. 

Lastly, don’t expect them to share. While they like to play around other children, kids at this age still play in parallel, and they have no idea how to get this right consistently. Have play dates but monitor them and keep expectations low. 

Developmental Milestones [Part 3: Preschool] >




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