Jangan risau sangat lagi, 16 months adalah masih awal, tapi I think worth checking dengan pediatrician or paediatrician for hearing screening and general development check, just to be sure, sebab yang you describe (respon selective, tapi paham some instructions) boleh jadi banyak reasons. A few mum friends I know ada anak yang gaklah respond to their names but understand commands perfectly, dan turned out fine lang, tapi better safe than sorry kan especially kalau ada speech delay worries. In the meantime, try talking to her more during the day, narrate what you're doing (macam "mommy tengah cuci pinggan"), point at things and say the words, dan engage her in songs or peek-a-boo, susah la especially when doing housework, I get it, tapi even 15 minutes of focused playtime makes a difference. Trust your gut as her mummy, and get that professional check done ye!