Many parents these days seem to obsessively celebrate their children’s developments by snapping photo after photo on their cellphone cameras.

Me? I record my son’s words in my notebook, on my phone, in my laptop. I want the audio record, and the written one; they capture one of the most evanescent aspects of childhood – the linguistic shooting star of early speech. I’m reminded often of its fleeting nature, even if sometimes I can do little more than marvel to myself.

Take one recent afternoon, when my preschooler, Leo, was riding his balance bike along the sidewalks of our neighborhood. It’s a pedal-less two-wheeler that allows him to careen along at a clip, sometimes to my dismay. Running alongside of him as we approached a corner, I began saying “yellow light,” my signal to him that it was time to slow down. “Lello light, lello light, lello, lello,” he said, laughing.

I laughed, too, but inside I thought, “How much longer do I have ‘lello’?” Someday soon, he will learn to say yellow. But nothing will ever sound as lovely as “lello.”

I also take pictures of him (and when he cooperates, video — that way I get the sound and the picture). And like other parents, I strain to capture just the right angle, trying time and again to get the perfect picture of his smile. But it’s different with how he speaks. Words are everything to me, and I want to record his words exactly as he speaks them. They need no embellishment or curation.

I’ve been recording the sounds that come out of Leo’s mouth ever since he was born four years ago. While working as an NPR station reporter, I incorporated bits of his speech into a feature story about how a baby’s ability to babble can be a predictor in autism detection. I included a sound bite of him saying, “Mamma,” and then gushed to my listeners that it was the best word I’d ever heard.

My son is my constant conversation partner. He’s also my muse.

Transcribing his words has become a personal linguistic project. I guess there’s something else, too.

For me, every conversation is a reminder of how I almost bungled this sphere of my life. Meaning: I almost didn’t become a mother. For years, I believed I wasn’t cut out for it. I saw myself as a selfish person with all kinds of albatrosses around my neck: I drank too much, my career seemed stalled, and so on. Plus, parenthood seemed like one more thankless task whose burden fell disproportionately on women.

Then I had a miscarriage, and in some uncanny moment of the veil lifting, I grasped what had slipped through my fingers. I had to have a child. Life — my life — would not be worth living without one.

Early motherhood wasn’t easy. In fact, it was nearly impossible for me, which is perhaps why the onset of the language era was so welcome. Like a thank-you gift. If this is part of my duties, I’m forced to conclude that far from not being motherhood material, I was born to have a lifelong conversation with someone that began with me teaching him, first and foremost, how to talk.

I find conversation cements everything we do. When Leo and I wake up each day, we retrieve the newspaper from the front porch and I say, “Let’s see if there’s a picture of President Obama in the newspaper.” How this routine developed I don’t know — but it’s tied to teaching him about the world through words. One morning a year or so into the ritual, he handed me a section of the newspaper and said, “You look for President Obama here, I’ll look for him in here.”

Only when I listen to him am I aware of time passing. Which is ironic. The aspect of motherhood that gives me the most joy also pinpricks me with reminders that it will all someday vanish. His speech is the first thing I notice when I travel for a few days without him. As I greet him, I listen closely to what he says, detecting shifts in his speech. After one trip, he said to me, “I have a story to tell you. Once upon a time, there were five tigers.” While I was away, apparently, we had entered a new era — one in which he could tell me a story.

I’ve found children sort out grammar and pronunciation on their own. But I’ve begun reinforcing his mistakes by repeating them. While looking at an illustration recently that showed only a woman’s torso, he asked me, “Why she not have foots?” Grabbing my notebook, I said, “Good question! Why she not have foots?”

Last year, I scribbled this thought in my journal: “The age of the full sentence is upon us.” We’d been watching an owl in our backyard in Atlanta, and when it suddenly took flight, my son said, “Owl flew away.” I was proud that he had strung a full sentence together. But I’d also recognized the milestone for what it was — my baby wasn’t babbling anymore. In fact, he was no longer a baby. Pretty soon, “lello” will be gone and all I’ll have is the written and audio record of its one-time existence. That, and the promise of a lifetime of future conversations.