When your baby in the high chair screams “da!”…you might know exactly what that means… down. Or did he mean dad? Or was it dog? Or doll?
When your baby looks into the room and excitedly says “ba!”….is it ball? Or bottle? Could it have been baby? Or boat?
Why do so many first words sound the same?
Speech is a very complex process, and it takes time to master moving from one sound to another. This is the hierarchy that we use:
Level I: Jaw movement (m, b, p, ah, aw, eh, uh)
Level II: Lip movement (ooh, oh, ee, ow, oy, ai, w, y)
Level III: Tongue movement (t, d, n, l, k, g, s, z, sh, ch, j, r, th)
Speech sounds are often learned in an order based on the complexity of the movement. For example, the reason that babies can often say “m” and “b” sounds early on is because it only requires the jaw moving up and down. Think of how the jaw moves when you say “mama”.
Some vowels also only require jaw movement, and thus, are the easiest to produce:
“ah” (as in apple)
“uh” (as in under)
“aw” (as in all)
“eh” (as in elephant)
Specific vowels require lip movement, which mean they are more difficult to produce:
The sound “ee” (as in easy) requires lip retraction. Therefore, it would be more difficult to say “bee” than to say “bah” (where only jaw movement is necessary).
Vowels “ooh” and “oh” require lip rounding. Therefore, it would also be more difficult to say “boo” or “bow” than it would to say “bah”.
Sounds that involve the tongue (t, d, n, l, s, k, g, etc.) require the speaker to dissociate the jaw from the tongue, or move them separately, which is a more complex movement. Therefore, “too”, which requires movement of the tongue, jaw and lips, would be more difficult to say than “boo”, which only involves movement of the jaw and lips.
Additionally, words that repeat the same consonants and vowels, are easier to produce than words that contain multiple consonants and/or different vowels. Hence, why saying “mama” comes before saying “mommy”.
So next time you notice your child having difficulty pronouncing a word, ask yourself:
What parts of the mouth are involved in the production of the sounds in this word?
Or all three involved?
So why does your baby say "da" for "down"?
Because your jaw, lips, AND tongue have to move to say "down".
These word approximations are your baby's way of simplifying words and are a completely normal part of speech development. As long as your baby consistently says a word approximation to mean the same thing in many contexts (e.g., every time he sees a dog he says "da"), then we still count it as a vocabulary word.