"Which of you shall we say doth love us most, That We our largest bounty may extend... ." King Lear- to his daughters Lear is talking in 3 rd person here about himself hes basically saying he wants his daughter to say how much they love him. "What Shall Cordelia Speak? Love, and be silent."Then poor Cordelia! And yet not so, since I am sure of my loves more ponderous than my tounge." Cordelia- To King Lear Shes basically saying that her he knows that her love is way weightier than any words she can say. Her father obviously doesn't know how deep Cordelia's love is. Because he takes this more as an insult and disrespect. "Nothing will come of nothing"Mend your speech a little, Lest Variant may mar your Fortunes." -Lear to Cordelia King Lear's response to Cordellia's failure to express her love for her father in words is symbolic of King Lear's madness in the play.
His madness is most clearly a manifest in his need for his daughters to show him heir love. In this one scene of Cordellia's failure to say that she loves him winds up driving him to madness. He then makes his problem even worse by banishing his daughter. This one scene sets up the rest of the play to drive Lear to further madness and his ultimate death. Later in the play after Lear has given Cordellia's land to Reagan and Goneril. He decides that he will live with both of them, it's the least they can do after is generosity.
After Goneril gets what's she wants she tells Lear to do away with 50 of his men. This only further drives Lear into insanity. What 50 of my followers in a clap? Life and death I am ashamed of you! -Lear to Goneril This is where the first instance where Goneril starts to show how much she truly "loves" her father.