Language development in babies is one of the most important milestones they can reach. After all, it shows that instead of just absorbing information, they're able to process it and reiterate it back to you. This advanced cognition is necessary to help better communicate their needs and respond to their environment.
To achieve this learned skill, babies rely on parents and caregivers to enforce their mother-tongue that already started making its mark on their brain in utero. This process is especially important right after birth when babies are adjusting to their new surroundings. Talking with your baby, especially if they heard your voice in the womb, triggers their brain to continue developing connections for language.
The stereotypical way of speaking to babies is what we refer to as "baby talk". In other words, taking regular words and sentences and twisting them to sound almost incomprehensible. Rather than "baby talk", parents and caregivers are encouraged to speak what BBC refers to as "baby-ese", in which adults respond to the noises that infants make by saying those same noises back to them and using proper pronunciation when speaking to them.
BBC also reports that studies show parents aren't speaking to their babies/children as often as they should; another factor that negatively impacts language development. Children need to converse with adults from the get-go. This includes eye contact and putting a genuine effort into trying to understand what they are trying to say. In addition, having the patience to allow the baby/child to try to speak without interrupting helps to encourage further learning.
Brain scans have shown that how adults interact with their babies/children in terms of language can be seen in the white matter of the brain. Children who have been exposed to regular conversations and direct focus on their language development were seen to have "stronger white matter connections in the brain in two major areas important for language, an increase that could speed up processing in these areas," says BBC.
A study led by Rachel Romeo, a neuroscientist and speech pathologist at Boston's Children's Hospital, showed that it wasn't only the amount of words a child is exposed to on a daily basis that helps their brain development. Rather, it is the number of direct conversations they have in which proper language use is present that makes a difference.
In having direct conversations and engaging in eye contact/using facial expressions from the newborn stage, a solid foundation for language development is established. In doing so, brain development speeds up and makes for easier learning down the road.