Babies are born communicating. Their cries and coos speak volumes. However, much-anticipated first words do not appear until 12 months later. By 18 months, the average child says about 50 words. By the time a child is ready to start school, their vocabulary will be an estimated 2,300 to 4,700 words.
Speech and language development takes time. Speech gradually becomes easier to understand; language gradually becomes more sophisticated.
Problems arise when speech and language milestones are not met. Left untreated, children who start school with speech and language difficulties face an increased risk of reading and writing difficulties, more bullying, poorer peer relationships and less enjoyment of school. So, what should parents expect of children at different ages?
'Normal' speech and language development
During the early years a child learns language - that is, converting thoughts and emotions into words. A child also learns speech - that is, figuring out the mouth movements needed to make speech sounds in words and deciphering the rules for how those sounds combine to form words.
For instance, children learning English learn that you can start a word with three consonants, but that the first consonant must be s, the second consonant p, t or k and the third consonant l, r, w or j as in splash, street and square.
By 24 months, a child should have at least 50 words and should be putting two words together. These two-word utterances should form basic sentences to request actions ("mummy up"), request objects ("more milk") and make comments ("big ball").
The child should also understand a range of words and follow simple commands ("Where's your nose?" "Where's Amy's tummy?"). Approximately 50% of a 24-month-old's speech should be understood by an unfamiliar listener.
Speech errors such as substituting easy speech sounds for more difficult sounds (saying "wook" for "look"), omitting sounds in words (saying "poon" for "spoon") and deleting entire syllables (saying "getti" for "spaghetti") are typical of this age.
Between 24 and 36 months, a child's speech and language ability should show rapid growth. By 36 months, 75% of what a child says should be understood by an unfamiliar listener.
By 48 months, a child should be talking in much longer, grammatically correct sentences. The child should be joining sentences using words such as "and" and "because".
As many parents will be able to confirm, children can ask an average of 107 questions an hour including: what, where, who, whose, why and how? A four-year-old should be able to explain recent events. However, they may struggle with some elements, particularly those involving time. "When" questions can be difficult for a child to answer.
Familiar two- and three-step instructions ("wash your hands and dry them") as well as less routine-bound instructions ("show me the monkey sitting under the chair") should be understood. Speech should be 100% intelligible to an unfamiliar listener by 48 months.
Errors such as "poon" for "spoon" should have disappeared. Some speech sounds may still be difficult: particularly "r" and "th", so that "rabbit" may still be pronounced as "wabbit" and "thumb" may be pronounced as "fum".
If your two-year-old isn't talking, or your four-year-old's speech is difficult to understand, seek the advice of a speech pathologist. Do not wait until your child starts school to seek help. Children can have better outcomes if they receive help before they start school.
Vocabulary and long-term outcomes
The amount and types of words addressed to children in the home from a young age correlates with their growing vocabulary. In an interesting longitudinal study of 42 children and their families, two researchers observed children at home once a month for an hour for 2 ½ years.
When they analysed their data according to family socio-economic status (upper socio-economic status, middle/lower socio-economic status and welfare) they noticed that the average child from a family on welfare heard 616 words per hour, the average child from a middle/lower socio-economic status (working class) family heard 1,251 words per hour while the average child from an upper socio-economic status (professional) family heard 2153 words per hour. When they extrapolated their results over four years of experience, they found that:
the average child in a professional family would have accumulated experience with almost 45 million words while an average child in a welfare family would have accumulated experience with 13 million words.
Not surprisingly, the children who heard more words, had bigger vocabularies and better language abilities by school age. Vocabulary size is important because children who start school with larger vocabularies develop superior reading abilities.
Children should be seen and heard, and engaged in conversation from a young age. If you are concerned about your child's speech or language development, seek the advice of a speech pathologist.
Elise Baker has received funding from the Australian Research Council, and the New South Wales Department of Education. She works for The University of Sydney. She is affiliated with Speech Pathology Australia. Natalie Munro has received funding from NSW SPELD. She works for The University of Sydney. She is affiliated with Speech Pathology Australia.