TOKYO, June 12 — For centuries, exhausted parents have relied on a familiar checklist when a baby starts wailing: hungry, sleepy, wet nappy, wind or simply in need of comfort.

Now, a growing number of parents in Japan are adding something else to the routine — artificial intelligence.

Meet the latest entrant into the booming world of parenting tech: apps that claim they can translate infant cries into actionable advice, turning late-night guesswork into something that looks a little more like a diagnostic dashboard.

One of the buzziest newcomers is Babylingual, a free app launched in March by 25-year-old Japanese father Moto Numazawa. The idea came not from a Silicon Valley lab, but from the living room of a first-time parent trying to prepare for the chaos of raising a newborn.

According to Kyodo News, Numazawa developed the app after his wife became pregnant, believing modern parents — especially those in increasingly common nuclear families — often have fewer relatives around to lean on for childcare advice.

In late April, he tested the app on his three-month-old son, Saku. Holding a smartphone close as the baby cried, Babylingual returned its verdict within seconds: “I’m hungry.”

The app didn’t stop there. It displayed a probability gauge comparing different possible causes of distress before suggesting: “It might be feeding time.”

The diagnosis wasn’t entirely off-base. About three hours had passed since Saku’s last feed. After being fed, he promptly drifted off to sleep in his mother Yu’s arms.

Babylingual draws on previous research indicating that babies may produce distinct vocal patterns linked to different needs. It sorts cries into five categories, while also allowing parents to save recordings to share with other caregivers and access voice-guidance features intended to help soothe infants.

Yu told Kyodo News the app had proven useful in situations where Saku’s needs were harder to decipher.

“I didn’t understand why he was crying when he had a build-up of gas in his stomach, so the app helped me,” she said.

Numazawa is quick to position the technology as an assistant rather than a replacement for parental instinct.

“Parents and children develop alongside each other,” he said. “I hope the app can help communication between them.”

Babylingual isn’t alone in this increasingly crowded corner of the AI economy.

Cross Medicine, a venture company affiliated with Tokushima University, has developed Awababy, an app trained using more than 160,000 recordings of baby cries alongside data on soothing techniques.

Awababy analyses infant vocalisations across 11 emotional categories and suggests possible responses. According to company president Koga Nakai, usage spikes during the middle of the night — precisely when sleep-deprived parents are least likely to have someone they can call for reassurance.

The company also believes the technology could help ease parental stress and potentially reduce the risk of post-partum depression. Local governments are already taking notice.

Mishima city in Shizuoka prefecture recently trialled Awababy with residents and is considering offering the service free of charge. Meanwhile, the town of Oyama has begun distributing user IDs to eligible parents of newborns.

For all the hand-wringing about AI replacing human connection, Japan’s crying-baby apps offer a different vision of the future — one where algorithms don’t take over parenting, but simply help decode one of humanity’s oldest mysteries.

After all, every parent wants the same thing at 3am: to know what the baby is trying to say.