I took my oldest son to the doctor last month for his Scout physical. He's 5'9" now, three inches taller than me. The growth that keeps taking me by surprise is invisible, though: his larynx is bigger than mine.
Your larynx sits right on top of your trachea. Its primary purpose is to protect your airway, but as a lovely bonus God designed the system so we can also use it to talk and laugh and sing and yodel. (Well, maybe God didn't intend that last one. Was there yodeling before the Fall? I am skeptical, personally.)
When you want to say something you bring your vocal folds together and push air through them. They pulse rapidly, creating a buzzing tone that you shape with your throat and tongue and teeth and lips. (And velum. The velum is the most unappreciated articulator, even though it is largely responsible for keeping you from sounding whiny and nasal.)
The size of your larynx plays a key role in the pitch of your voice, because more mass in the vocal folds = fewer pulses per second. An average man's vocal folds might vibrate 120 times per second, meaning his voice will fall about an octave below middle C. An average woman's vocal folds will vibrate about twice that fast, giving her a voice roughly an octave higher. My voice is pitched a smidge higher than usual, at about the E above middle C. (You can hear me talking at the beginning of the video embedded here if you're curious. I don't walk around talking like Glinda the Good or anything.)
So I am used to my son's big pre-man feet, and I accept that he's taller than me forevermore. But his voice keeps throwing me for a loop. I keep turning around and thinking, "Who's that MAN in my house? Why is there a MAN in here?" And then I think, "...whoa, that's my son with that big manly voice."
Tonight in the van I was trying to estimate his fundamental frequency (I bet you wish your mom was a speech pathologist too!), humming along as he spoke. I'd put it at about the G below middle C -- not so terribly low, but unmistakably different from his brothers' voices.
I know it will just keep dropping as he matures, since one of the effects of androgens is to enlarge the larynx. You can measure growth with pencil marks on the wall, sure, but you can also measure it with a descending scale on the piano.
Tonight I was imagining a future in which all of my boys will go tripping down that scale, and it left me a little wistful. I'm going to hold onto my memories of our drive tonight -- of my firstborn and my baby talking together, her chirping soprano interweaving with his beginner baritone.
Oh how interesting! We all project what we know onto our kids, but to hear growing up via speech pathology parenting is fascinating.
It did occur to me recently that all of our boys will likely be taller than both my husband and I. I'm 5'7" and he's 5'10". I figure the male equivalent of my height is about 6', so there's a good chance our boys will be somewhere near that and we'll both look up to them some day. So strange.
I love hearing what's coming from someone two kids ahead of me.
Posted by: Amy F | June 12, 2011 at 10:52 PM
Love this one. Expect a link from me.
Posted by: bearing | June 13, 2011 at 07:04 AM
Love, love, love this post. My thirteen-year-old is best at tenor, but can still sing soprano:) And I agree with you about the under-appreciated velum. Try singing (or speaking) without one functioning properly.
Posted by: Marcie | June 13, 2011 at 11:24 AM
You have me nearly in tears right now. I guess I want to mark the pitch of their voices (which is oh, so high, particularly Kelvin's) and then watch as it drops lower. :( I'm sure I'll be as shocked as you are when you hear that "MAN" talking in your house.
Posted by: Lilian | June 13, 2011 at 06:16 PM
Oh, I love this. I am constantly startled by Tre's voice these days, and then I wonder why it should be a surprise.
Posted by: Kira | June 13, 2011 at 11:28 PM
This is fascinating, and makes me want to start recording my little guy. I have a few instances of his tiny baby voice, but I want to get more of his pre-school sound. I don't know if it's technically possible, but I would SWEAR I can tell a difference in his 5-year old voice, compared to some of the other little voices in his pre-school: maybe it's just that I know his voice so well, and I know it goes with him (like penguins, picking their chick out of a crowd??), but I'd swear I can also tell that he's a BOY. And as a singer, I find myself wondering what he'll sound like as a teenager (when I hope to coax him into the youth choir associated with my chorus), and eventually as a young man. I sing soprano, mostly, but I often drop to an alto harmony in church, and my speaking voice is hard for some people to place. My husband, if he sang, would probably be...a second tenor or very light baritone. (He has a lighter voice than my friend who sings baritone/bass, but can pop up to tenor if there aren't any others available at Easter!) Are such things hereditary? If general size is, will the size of the larynx follow? Love this stuff.
Posted by: Kristin | June 16, 2011 at 10:54 AM
Ok, so my ear isn't good enough to tell what key my fourteen year old's voice has dropped to, but the 8in growth spurt, the acne breakouts, the two sizes up shoes are all obvious visuals of adolescence. We put on a video the other day from about 10 years ago and didn't recognize the little boy voice coming from our oldest. Is sound the easiest thing to forget? Or am I just not attuned to it?
Posted by: Emily J | June 16, 2011 at 11:20 PM