Hindi pa kailangan mag-worry agad, marami akong kaibigan na ganyan din ang baby nila at nag-develop lang talaga ng delayed, but since he had those words before at biglang nawala, mas better na i-check with your pedia para peace of mind, kasi sometimes may underlying thing na pwedeng ma-address early pa lang. Ang 16 months pa lang siya, and every baby's timeline is different talaga, pero ang regression (yung nawala ang words) is something worth monitoring with a professional para ma-guide ka ng tama sa next steps.