Crying without a clear reason can be a major source of anxiety for parents. As families look for new ways to navigate the uncertainty of early childcare, Japanese developers are rolling out AI-powered tools designed to identify the possible causes of a baby’s distress. One of them is Babylingual, a free app released in March by Moto Numazawa, a 25-year-old father in the Kanagawa prefecture city of Chigasaki, near Tokyo. In late April, Numazawa held his smartphone up to his three-month-old son,..