This is not an uncommon question, especially in the world of toddlers and preschoolers. Children start using spoken language (words and short sentences) long before they are actually able to produce all the speech sounds for the words and sentences that they want to say. There are roughly 45 speech sounds in the English language. This confuses people sometimes, because there are 26 letters in the alphabet we use to write words down. But remember that one alphabet letter (or "grapheme") can stand for a number of different speech sounds (or "phonemes"). Take the letter "c" for example--in words such as "cat," it makes a /k/ sound, but in words such as "face," it makes a /s/ sound. So, while there are 26 letters in our written alphabet, there are 45 sounds in our spoken words. And, even at the age of three, the great majority of children are still working on producing at least 18 of those speech sounds.
Speech sound development is predictable, in that it typically unfolds in a somewhat similar way across children. Most children, for example will make a /w/ sound for /r/ for a long time--this is fully expected and of no concern. Ironically, speech sound development is also quite variable, in that some children produce words clear as day from almost the moment they start talking while others take much longer to produce speech sounds clearly. As a speech therapist, it's my job to help figure out when a child's speech is so distinctly different from normal that the child would benefit from therapy. It's not always easy--and even as speech therapists, we don't always agree! There are some general guidelines, though, that can be helpful to share with parents of young children who are worried about their child's speech. And that, my friends, is what I'm going to share with you today.
Intelligibility is a fancy word that simply means "how much of a child's speech is understood." The general guidelines for intelligibility in young children are as follows:
- A 2 year old is usually understood by others about 50% of the time
- A 3 year old is usually understood by others about 75% of the time
- A 4 year old is usually understood by others nearly 100% of the time
Children usually develop certain speech sounds first. Then, as they grow, they learn to produce new speech sounds along the way. Here's a general picture of which sounds are easy, which are harder, and which are the hardest:
- Easy speech sounds: Vowels, p, m, h, n, w, b, t, d
- Harder speech sounds: k, g, f, v, "ng" (as in ring), and y (as in "yellow")
- Hardest speech sounds: r, l, s, "ch," "sh," j, "th" and "zh" (as in the end of the word "garage")
To find out what ages kids usually develop these speech sounds, you can take a peek at this:
Speech Sound Development Chart (developed by Eric Sander in 1972).
It's not perfect, and there is disagreement in the field of speech therapy about how accurate it is, but it's a great guideline for helping you to get a basic picture of when speech sounds are usually produced accurately. The beginning of each black bar represents the age at which 50% of children produce the sound correctly, while the end of each black bar represents the age at which 90% of children produce the sound correctly. As speech therapists, we generally don't get too excited about a certain speech sound error until a child isn't producing it when 80-90% of his peers are.
Finally, any discussion of speech sounds is incomplete without talking just a bit about how children use those sounds in what we call "syllable shapes." Syllable shapes refer to the way that we put consonants and vowels together to make words. This can get a bit tricky to think about, because most of us are used to thinking about how we put alphabet letters together to spell words, rather than how we put sounds together to say them. A full discussion of this is too complex (and way too boring) to get into here, so I'll just ask that you remember that, for the purpose of this post, we are talking about sounds, not letters. Okay? Okay.
When we shorthand syllable shapes, we write C for consonant and V for vowel (easy enough, right?). So a "CV" word would be "me". One consonant + one vowel. A CVC word would be "mom." Got it? Good.
Here, then, is what we know about the development of syllable shapes:
- Easiest Syllable Shapes: V-V (uh oh), CV (me), VC (up), CVC with the same consonant (mom) and CVCV with the same consonant (daddy).
- Harder Syllable Shapes: CVC with different consonants (pat), CVCV with different consonants (tummy), and CVCVCV words (banana)
- Hardest Syllable Shapes: Words with two or three consonants in a row (black, street) and long words (dictionary).
Combine all that together, and you'll start to find the words that are easy for children (me, boo, bye, mama, dada, up), a bit harder (hat, pony), harder still (dog, kitty, goat), and the hardest (Gregory, licorice, motorcycle). When we speech therapists work with children with speech sound difficulties, we often start with the sounds that are the easiest and put them into the easiest syllable shapes...and then we go from there up, up, up the ladder of speech sound development.
Whew. With all that information, isn't it amazing that our kids ever get it right? Luckily, most of them do, with very little help from us at all. And if they don't? That's what speech-language therapists are for! :)
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