Dog. Shoe. Ball. Disparity.

Brain development occurs incredibly fast in early life. Anybody who has raised a child from birth has noticed startling changes in what a young child can do, seemingly overnight.

About two-thirds of adult brain size is reached by age 2½ to 3. Ninety percent of brain development occurs by age 5.

This is the most crucial time for formation of synaptic pathways that are the basis of social and emotional development and reading and math abilities. If these pathways are not adequately developed, costly interventions during K-12 education and beyond may be necessary.

Positive social interactions and sensory stimulation promote positive behaviors in babies and young children and protect against chronic health problems in adulthood. An absence of positive interactions or presence of repetitive or prolonged negative stimulation put a child at increased risk of mental health, learning, and behavioral disorders.

When they reach adulthood, these children are more likely to earn lower wages, use more social services, experience higher rates of chronic health problems such as diabetes and coronary heart disease, and tangle with the expensive and overburdened criminal justice system.

In our education system, early language development is one of the most important areas to focus our resources on to address these challenges.

Every word a child hears early in life builds their brain. By 18 months of age, disparities in vocabulary between children of different socioeconomic backgrounds are observable. By age 3, children with low vocabulary exposure will have working vocabularies of 400-600 words, while a child with high vocabulary exposure (nearly 30 million more words than the first group) can use 1100 words on their own.

What difference does this make? A child’s vocabulary at age 3 is highly predictive of their reading scores in third grade. It is significantly correlated with IQ scores and academic achievement.

Thus, the best return on investment is in early childhood education, serving children when their brains are most malleable. It’s the most advantageous time to narrow the achievement gap–the disparity in learning–which becomes harder to overcome as the child ages and usually widens over time instead.

Coaching parents to speak more words directed at their children and frequently share simple conversations with them is also critical. Even when parents have less formal education or are low-income, their children have better language outcomes if they verbally engage with them more often.

How big is the return on investment in these programs? Every dollar spent on early childhood education saves taxpayers up to $13 in future costs. It is one of the most sensible investments we can make, and it’s the fair thing to do.

Putting our resources into both quality early childhood education and family initiatives for increasing children’s language exposure at home is becoming more critical as our economy shifts to a knowledge-based workforce. Our economic strength moving forward depends on giving more children better opportunities to succeed in school.

The net gain for society includes a higher tax base and stronger communities. In Minnesota, we have good overall outcomes compared to other states, but our dirty secret is that we have one of the largest achievement gaps between white and minority children. We must especially do better at extending opportunities to minority populations within our state.

Minnesota’s late Senator Paul Wellstone often used to say, “When we all do better, we all do better.” Our understanding of how to increase the school achievement gap by bridging the vocabulary skills gap in young children is a powerful tool to help us all do better.