One of the cardinal features that distinguishes toddlers from infants is the use of language. Why is language so important? Language is a vehicle for symbolic thought. Unlike furniture or food, words are not useful objects in and of themselves. Words are useful only in their ability to symbolize something else. Why is that important? The capacity for symbolic thought removes the child from the prison of the here and now. Words take the child into the future and the past and to any place that can be imagined. Of course, words are also critical tools for communication. Prior to language the parent has to guess the child’s wants and needs. After children can talk, they can tell their parents what they want.

The precursors to language start in the first few months of life. First the child must develop the capacity for complex vocal sounds. At two months, babies start cooing, or producing vowel sounds. At four months, they start babbling, which involves combinations of consonant and vowel sounds. Over the rest of the first year, the babbling becomes increasingly complex and tailored to the native language of the child. Around ten months, their babbling becomes strikingly melodic, mimicking the intonation and rhythm of their native language.

There is also unmistakable emotional content. In fact, it can be quite amusing to listen to a ten-month-old baby clearly communicate emotion and intent in the complete absence of intelligible words. For example, an 11-month-old baby crawled into his mother’s chair, which she had recently vacated. He picked up her coffee cup, and looked at her adult friend who had just been conversing with his mother. Putting his elbow on the table, he immediately started babbling. “Ah bah doo be dah. Doo doo bah me mah!” he said with evident purpose. “He thinks he’s talking,” his mother explained. “He wants to join the conversation.”