Your baby will learn to talk during his or her first two years of life. Long before your baby utters a first word, he or she is learning the rules of language and how adults use it to communicate.

Your child will begin by using the tongue, lips, palate, and any emerging teeth to make sounds (ooh and ahh in the first month or two, babbling shortly thereafter). Soon those sounds will become real words ("mama" and "dada" may slip out and bring tears to your eyes as early as 4 to 5 months).

From then on, your baby will pick up more words from you and everyone else around. And sometime between 18 months and 2 years, he or she will begin to form two- to three-word sentences. As your baby makes mental, emotional, and behavioral leaps, he or she will increasingly be able to use words to describe what he or she sees, hears, feels, thinks, and wants.

When and how it develops

Here's how you can expect your baby's talking to progress. (If he or she is being raised in a bilingual environment, the number of words he or she can speak will be split between the two languages your child is learning.)

In utero
Many researchers believe the work of understanding language begins while a baby is still in utero. Just as your unborn baby gets used to the steady beat of your heart, he or she tunes into the sound of your voice. Days after birth, your baby is able to discern your voice among others.

Birth to 3 months
Crying is your baby's first form of communication. And one cry doesn't fit all: A piercing scream may mean he or she is hungry, while a whimpering, staccato cry may signal that he or she needs a diaper change. As your baby gets older, he or she will develop a delightful repertoire of gurgles, sighs, and coos.

As for your child's ability to understand language, he or she is starting to pick up what words sound like and how sentences are structured as he or she listens to those around him or her. Linguists say babies as young as 4 weeks can distinguish between similar syllables, such as "ma" and "na."

4 to 6 months
At this stage, your child will start to babble, combining consonants and vowels (such as "baba" or "yaya"). The first "mama" or "dada" may slip out now and then. Though it's sure to melt your heart, your baby doesn't equate those words with you quite yet. That comes later, when he or she is almost a year old.

Your baby's attempts at talking will sound like stream-of-consciousness monologues in another language, with endless words strung together. Vocalization is a game to your baby, who's experimenting with using the tongue, teeth, palate, and vocal cords to make all sorts of funny noises. At this stage, babbling sounds the same, whether you speak English, French, or Japanese in your home. You may notice your child favoring certain combinations ("ka" or "da," for example), repeating them over and over because he or she likes the way they sound and how his or her mouth feels when saying them.

7 to 12 months
When babbling and vocalizing now, your baby will sound as if he or she is making sense. That's because your baby is trying out tones and patterns similar to the ones you use. Foster his or her babbling by talking and reading to him or her.

13 to 18 months
Now your child is using one or more words, and he or she knows what they mean. Your child will even practice inflection, raising his or her tone when asking a question, saying "Up-py?" when he or she wants to be carried, for example. Your child is realizing the importance of language, tapping into the power of communicating his or her needs.

19 to 24 months
Though he or she probably says about 50 to 70 words now, your child may understand as many as 200 words, many of which are nouns. Between 18 and 20 months, he or she will learn words at the rate of 10 or more a day (so watch your language!). Your child will even string two words together, making basic sentences such as "Carry me."

By the time he or she is 2, your child will use three-word sentences and sing simple tunes. Your child's sense of self will mature, and he or she will start talking about likes and dislikes, as well as what he or she thinks and feels. Pronouns may confuse your child, which is why you may hear "Baby throw" instead of "I throw."

25 to 36 months
Your child may struggle for a while to find the appropriate volume to use when talking, but he or she will learn soon enough. He or she is also starting to get the hang of pronouns, such as "I," "me," and "you." Between ages 2 and 3, your child's vocabulary will grow to up to 300 words. He or she will string nouns and verbs together to form complete, simple sentences, such as "I go now."

By the time he or she turns 3, your child will be a pretty sophisticated talker. He or she will be able to carry on a sustained conversation and adjust his or her tone, speech patterns, and vocabulary to match a conversation partner. For instance, your child will use simpler words with a peer but be more verbal with you. By now he or she may be almost completely intelligible. Your child will even be a pro at saying his or her name and age, and will proudly oblige when asked.

Your role

You can help your child's language skills along by providing a rich and nurturing communication environment. The most important things to do:

Talk. Research shows that children whose parents spoke to them extensively when they were babies have significantly higher IQs and richer vocabularies than other children. You don't need to chatter nonstop, but speak to your baby whenever you're together. Describe what you're doing, point things out, ask questions, sing songs. (Although some baby talk is okay, resist the temptation to coo and babble. Your child will learn to speak well by listening to you speak well.) 

Read. Reading to your child is a great way to expose him or her to new vocabulary, the way sentences are put together, and how stories flow. As a baby he or she will delight in the sound of your voice, as a toddler he or she will enjoy the stories and pictures, and by the time he or she is a preschooler your child may even jump in to tell you what's going on in a book. 

Listen. When your child talks to you, be a good listener – look at him or her and be responsive. Your child is more likely to speak up when he or she knows you're interested in what he or she is saying.

When to be concerned

You're the best person to gauge your child's speech development. If he or she is showing any of the signs listed below and you feel concerned, it's a good idea to discuss the possibility of a language delay or hearing problem with your child's doctor.

If it seems necessary, your doctor will refer your child to a pediatric speech-language pathologist for an evaluation. (A searchable directory of certified therapists can be found on the American Speech-Language-Hearing Association's website.) Alternatively, your doctor's office, daycare provider, or local school might be able to direct you to an early intervention program in your area – usually coordinated through the county or public school system – that will provide free screening for language problems.

Some signs to look out for:

6 to 12 months
Your baby isn't making (or even attempting to make) any sounds or eye contact with you, or stops babbling at around 6 months.

13 to 18 months
Your child isn't saying any words by 15 months (including "mama" or "dada"), didn't babble before his or her first birthday, is unable to point to any body parts, or you still can't understand a word he or she is saying by 18 months.

19 to 24 months
Your child rarely attempts to speak or imitate others, drops consonants from words (saying "ea-ut" for "peanut," for example), doesn't seem to get frustrated when you can't understand what he or she wants, or only uses single words – no combinations.

25 to 36 months
Your child continues to drop consonants, has difficulty naming most everyday objects, hasn't started to use two- or three-word phrases, or by age 3 cannot be well understood by someone who doesn't know him or her.

If your child stutters, it doesn't necessarily signal a problem. Stuttering is a normal phase, especially when your child's ability to communicate is expanding so rapidly. Sometimes he will be so excited to tell you what's on his mind that he can't get the words out fast enough. But if his stuttering continues for more than six months, or if it's bad enough that he tenses his jaw or grimaces in an effort to get the words out, talk with his doctor about it.

What comes next

As your child grows, he or she will become more of a chatterbox. There might be moments when you long for those peaceful days of speechlessness, but for the most part, you'll delight in his or her play-by-plays of what happened at preschool.

By age 4, your child will use about 800 words. He or she will begin to understand and use correct tenses, along with the contractions "won't" and "can't." Oh, and get ready for every why, what, and who question under the sun.

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