As infants' brains continue to develop, infants also develop the ability to communicate; to comprehend and produce spoken language. Babies learn language by taking in information through their senses of hearing and sight as they learn to process the meanings behind those sights and sounds. They use their mouths, tongues, and ears as they learn to mimic the sights and sounds of other people in order to create their own sounds and communications. In order to learn from their environment, babies need functional hearing abilities and a well-formed mouth, lips, vocal chords and tongue. They also need a well-formed brain, for it is the brain that provides for the baby's instinct to mirror, copy and mimic facial expressions and movements they encounter. Any questions caretakers have about their baby's ability to hear to use their mouths properly (in a mechanical sense), or to copy and mimic faces and sounds should be brought to the attention of the baby's pediatrician as soon as possible so that any necessary therapy or treatment can be provided at the earliest possible time. Catching problems before they become problems can help to avoid developmental delay.
Babies' and young children's language development is strongly influenced by the language they hear spoken around them and to them. The more babies are exposed to language, the more opportunities they'll have to practice their developing communication skills. This is why it is a good idea to interact with your child regularly, speaking with and reading to him or her whenever possible.
The following section of this article will discuss the average ages at which many infants will reach certain language milestones important for understanding and creating speech. Remember that each child is different, and will reach different milestones at their own rates. If you have any concerns about your child's development, contact your pediatrician or family doctor.
When infants are first born, they do most of their communication through crying. They cry to tell caregivers they are hungry, tired, or uncomfortable; have a dirty diaper; are in pain; or just want some attention and affection. However, infants are already learning about spoken language from birth. As their caregivers talk to them in their field of vision, 8-10 inches from their face, they will copy the mouth movements the caregivers are making. Around age 2 to 3 months, infants begin cooing and making soft, exaggerated vowel sounds to show pleasure or excitement. Babies are able to do this because their larynx (vocal chords) and other parts of their throat change to allow them to make these sounds.
By age 3 to 4 months, babies will add more verbal sounds and start to make the consonant sounds of b, k, m, g, and p. By around age 4 months, babies will begin to put vowel sounds and consonant sounds together to form nonsense words such as "gaga" and "ahpoo" as they start to experiment with how sounds can be linked together. As well around this age, infants can blow through their lips and may blow bubbles to practice using and controlling their lips and mouths. Babies continue to practice making those sounds, as their brains learn how to interpret and process the communications they hear. By around age 5 months, babies are learning the musical sound and speech patterns of their caregiver's native language, which is the language they hear the most. As they continue to practice making sounds, they will begin imitating their first sound patterns. Also around this age, babies are using non-verbal cues to communicate their thoughts and feelings to those around them. They will cling to their caregivers, push them away when upset, and turn their heads when they don't like something. Around age 6 months, they begin to babble. This allows them to connect consonant sounds with vowel sounds in ways that are used in their native language to make distinguishable syllables. Babbling allows children to imitate the sentence length, intonation, and rhythm of adult speech as they begin to learn how to form verbal thoughts.
As babies enter the second half of the first year, their ability to understand how language works and how to communicate continues to become more sophisticated. By around age 7 months, babies begin taking turns "speaking" with others instead of talking at the same time as others do. They may initiate conversations with others as they begin learning how conversation between people works. Meanwhile, babies will also try to imitate sounds caregivers make, especially animal sounds such as "moo" (English for the cow's sound). By around age 8 months, babies begin to connect sounds they and their caregivers make to actual ideas and thoughts that can be universally understood. For example, when a baby hears the word "milk," she knows she'll be getting her bottle soon; when she says "bub," she'll get her beloved stuffed bear. Also around this age, they build on top of the syllables they started making earlier and now link syllables in more understandable words such as "da-da." Babies continue to add new sounds to their verbal menu, adding new consonant sounds such as t and w.
Near the end of their first year of life, babies begin to put together all the language lessons they've learned so far. Between the ages of 9 to 12 months, babies begin to say their first real words, such as "mama" and "dada." During this period, they may slowly add a few more words to their vocabulary. By age 12 months, some babies may have as few as a 2-3 words in their expressive vocabulary, while others may have a dozen.
It is important to remember that babies' receptive language is much more developed than their expressive language at this point. While babies may speak few words, they are able to comprehend the meaning of hundreds more. They will begin to show this understanding as well. By around age 10 to 11 months, babies may begin communicating by pointing or nodding in agreement or disagreement with what caregivers say. Around age 12 months, babies will begin to show word and sentence comprehension as they point to a dog in the picture when prompted or nod their head when asked if they want a cookie.