I understand you are busy at work when she calls (daily!!)
and hence u get irritated, or you feel embarrassed (strange) not knowing what to talk (unfortunately) to keep the conversation with your wife going.
prior being the case - make her understand you are busy at work and cant do justice to both at same time...and you have life's time to talk to her after work...

later being the case - discuss what she like, this will take ages for you to understand,, :-).