0-5
Making Progress
All children develop at their own rates, but there are some generalisations that parents can look for to gauge their child's progress. While parents needn't worry if their child's language development doesn't progress according to the "norms," they should be sure that the child continues to make progress. Stalls in language and speech can signal a need for professional intervention.
Newborn to 3 Months
Even very young babies seem to respond positively to being spoken to, turning their heads toward the sound of a familiar voice. Babies' first verbal communication is through crying, with varying sounds to indicate hunger, pain, and a need to be held. By the three mark point, many babies are making happy cooing sounds, especially in response to similar sounds made by their primary caregivers.
4 to 6 Months
Baby babble is common during this timeframe, with babies stringing sounds together that may begin to sound like "talking." Babies this age often have a few favourite sounds that they remember and repeat.
7-12 Months
Babies' very first recognisable word is often uttered during this stage, much to the delight of parents. The overall quality of a baby's speech is improving now too, with increasing consonants and varying long and short vowel sounds.
1-2 Years
Toddlers have an impressive understanding of words, although their own vocabularies are still fairly limited. They display the ability to point to requested objects and to respond appropriately to requests, indicating their understanding. Their own vocabularies are growing at a rapid rate, with new words and even short two and three word phrases being added regularly. "More milk" and "go car now" are within the capabilities of toddlers.
2-3 Years
With speech becoming much clearer, two to three year old children are able to communicate with people outside of their families (close family members may have been the only ones able to understand their previous attempts at language). They are also becoming much more descriptive, readily using adjectives.
3-4 Years
Sentence structure begins to improve (but is not yet consistently correct) and storytelling becomes a favourite pastime. Brimming with stories about their daily activities, children this age are happy to engage in conversation. Stuttering may appear now for some children. If so, parents should seek the advice of a speech-language pathologist.
4-5 Years
Now able to hold detailed and prolonged conversations, four to five year old children are able to speak clearly and in mostly correct sentences. Vocabularies are extensive, with kids consistently picking up new words and phrases. At about four years, some children speak with a lisp, but this is usually outgrown soon after. Sounds get easier for many kids by the time that they reach their fifth birthdays, with some kids still having difficulty with "v," "r," or "th" sounds. While this is common and not usually a cause for concern, parents may wish to consult with a speech pathologist if their child has continued difficulty.

ADDITIONAL
Birth to 3 Months
Very young babies cry in order to communicate their needs. While some feel that the cries are indistinct, others believe that infants make specific sounds for varying needs (i.e. Priscilla Dunstan). In any case, babies do communicate their needs verbally and wise parents are quick to react, further encouraging their babies to "talk."
Related Reading... * Participating in Your Child's Language Development * Can Baby Sign Language Delay Speech Development? * Bringing Up a Bi-lingual Child * Dunstan Baby Language * Language Development in the Second Year
4 to 6 Months
At about this time, babies start to babble, showing a special fondness for repetitive sound. Often, they are a combination of consonants and vowels, such as "baba" or "gaga." Occasionally, babies of this age will choose "mama" and/or "dada," sure to delight their proud parents, but experts believe that