When you have your first child, check-ups with the pediatrician sometimes feel like a quarterly review of your parenting job performance. Are you doing it right? Is he gaining weight? Crawling? Cruising? (I still don’t know what cruising is.) Even when delivered kindly, these questions can cast a spotlight on your deepest-felt inadequacies and shortcomings.

But it wasn’t until my son’s check-up at 15 months that I felt truly stumped.

“How many words does he have?” the nurse practitioner asked during the exam.

“What? Oh . . . I’m not sure.” I said. I hadn’t counted them. He had so few. How many was he supposed to have? I thought, frantically trying to remember what the parenting blogs and books had said. The nurse practitioner, sensing my panic, asked helpfully, “Does he say mama and dada?”

“I guess?” But, as I searched my mind for evidence, I realized he didn’t. He pointed. He made eye contact. He said a rolling “Dadadada,” sometimes in the general direction of my husband. But he never said mama. He didn’t say ball or milk. He was sharp and deeply observant, watching the interactions of the grown-ups around him with his brow slightly furrowed. But he didn’t talk.

“Don’t worry,” said the nurse practitioner. “We’ll check again at 18 months.” So, of course, I worried. At home, I became fixated on trying to goad him to talk. My husband and I waved blueberries just out of his reach, saying “More? More?” in the hopes that he would mimic us. We pointed at and named every object in sight. The doctor had said to talk to him as much as we could, so I gave an ongoing monologue throughout the day, chatting idly like a late-night host with no audience while I washed dishes, picked up toys, drove us to the library. Still, silence.

Two months after that doctor’s visit, I was at the playground, watching my son play next to another child roughly his age. “Mama, doggy!” the little girl called to her mother, and I realized I couldn’t picture my son doing the same. On the walk home, I cried as I looked up the number of our county’s early intervention services, pushing the stroller with one hand while I called.

That call felt like waving a white flag. My son isn’t perfect, it said. I can’t fix this. Please help me.

The woman who took my call asked me a series of questions. I expected her to tell me I was overreacting, that I was just a worried first-time mom, that I was wasting her time. But, instead, she scheduled an appointment for him to be evaluated for speech therapy. I hung up, stunned. What had I done? Why didn’t I just listen to the doctor and not worry?

A week later, two therapists and a case worker arrived at our house for the evaluation. They wore jeans and sneakers and knelt on the rug in our living room. They showed my son a series of toys and books, and took notes while he played.

One of the therapists pulled out a three-ring binder. Each page inside had a large, colorful picture on it. Ball. Bath. Dog. Car. I could see in my son’s expression that he knew what most of the objects were, but he couldn’t say anything beyond a few consonant noises.

HE KNOWS WHAT THEY ARE! I wanted to shout from my tense perch on the couch. HE’S FINE!

One of the therapists set her notebook down on my coffee table. “Your son is very bright, but he has a significant speech delay. He definitely qualifies for getting help with his speech.” Definitely. Did she have to say definitely?

Our speech therapist called herself Miss Kelly. She came over to our house every Friday and sat with my son on our living room floor. (I was vacuuming the rug more than I ever had, an unexpected benefit.) She brought a huge tote bag filled with puzzles and toys, including a block tower covered with pictures of animals and small plastic cars that connected to each other with magnets. He loved it.

I was skeptical in those early weeks. How could this person, a near-stranger, fix this by playing with him for 30 minutes a week when his own mother had tried so hard and couldn’t?

But, after a month or so, he started to make more sounds. She taught him baby sign language. One night at dinner he did the sign for “more” and said “muh muh muh”. I cried as I pulled a clementine apart for him to eat.

On a cold Monday morning, we sat on our couch together and watched the garbage truck rumble down our street. “No,” my son said, pointing. “Garbage truck,” I said. “No!” he said, insistently, and I realized he was saying “snow, snow” at the snowflakes that had started falling. Something was happening.

Then, one day before the sun came up, I heard him stirring in his crib. I groaned, not ready to get out of bed, until I heard him call from across the hall: “Mama! Mama!” and then, longer, more impatient: “Mammmaaaaaaaa!”

During one session, Miss Kelly remarked on the progress my son was making. I told her, a little sheepishly, how hard it had been for me to face his problem, and to have a professional put a label on it.

“He’s the same kid he was before you made that call,” she said.

My son’s progress with speech was like the slow burst of a dam—a trickle at first, building into an unstoppable gush of thoughts and sounds. These days, he uses his words—the words we fought so hard for together—to educate us on his encyclopedic knowledge of the Star Wars universe. Each word still sounds so sweet. They’re all little lessons for me.