my 18months old son doesn't call me mama/nanay

my son is talking naman.. mostly english words po ang sinasabi nya. he will say the word when i ask "what is this?". i think he can say more than 20 words. knows alphabets, some shapes, colors, and can even count from 1-10. he can also follow instructions like come hear, no, get the ball, etc. my concern is he doesn't call me mama/nanay. kapag tinuturuan namin sya ni hubby he is just looking at us. then laugh.. i am so frustrated on how to teach him to call me mama.. he used to call my husband tatay/papa.. i think he recognized me. kasi kapag umaalis ako and come back to our house sumasalubong sya and smiling at me.. but still dont call me mama. im a full time mom. most of the time sa bahay lang ako.i only go outside during grocery time or if i go to church.. pero most of my time i spend it with my baby. nakakasad lang kasi pag hindi nya ko tinatawag na mama.. 😔🥺 #pleasehelp #firstbaby #advicepls #firstmom