babbling ?

my baby has ways very been chill never cry’s unless hungry can entertain herself for hours and sleeps amazing she’s pretty content she use to have little conversation with us it stoped around 3.5 months now just turned 5 months and has completely stopped I brought it up to pedi who didn’t seemed concerned said they will do hearing test at 6 months she dose react to sound are you babies talking babbling and if so when ? I’m a first time mom and always so nervous