Toddler doesn’t take part in conversation

She knows her abc 123 can label some objects but if you want to engage her in conversation she shows no interest like if you say drink some water she will drink it but if you ask do you want more food or anything she won’t say yes or no or gesturing with head but just grunts unless she gets more . She is good at malls and at stores but still not friendly with her aunts or cousins whom she sees every other month. She wonts try to call us by saying daddy or mummy but knows who daddy is . If she go to a relatives house she starts crying as soon as she enters there. She is very responsive shows everyone us plays with us but doesn’t use any labels for things around us . Not calling cousins by their name or not trying to say aunty . I’m really concerned. She makes excellent eye contact brings everything to you for help but at times I think whether she understands what we are saying or not. Please give any suggestions to encourage her to engage in conversation.