How is language used to show the relationship between Olivia and Viola in 1:5?

In Act 1 scene 5 we witness the first meeting of Viola, dressed as a man and calling herself Cesario, and Olivia. During this scene Olivia uses language to hint at the fact that she loves Cesario but at the same time Viola is using language to hint at the fact she is indeed a woman.

We see hints of Olivia falling for Cesario as she sends away Maria, "Give us the place alone.", which makes the audience question why she wants no one else present. She then, clearly impressed by Cesario, tries to impress him too; She uses her beauty. She unveils, "we will draw the curtain" to "show (him) the picture".

Just like with Feste, we see that Olivia likes Cesario's cheekiness and boldness. We know this because she let's Cesario get away with being rude, only commenting, "Yet you began rudely." Another interpretation of this is that at the beginning of the meeting Olivia isn't impressed by Viola/Cesario's boldness, but by the end has warmed up to 'him' and stops treating 'him' as a servant, or another one of Orsino's messengers whom she finds annoying. "From the count Orsino, is it?" "We'll once more hear Orsino's embassy." In this interpretation she goes from using a more reserved tone, answering little to Viola's long texts, "Tell me your mind." to using a more interested tone, "What is your parentage?" The shift in her feelings are due to how Viola presents herself and uses her language to give Orsino's message in a different way. Instead of reading his script, "Most sweet lady -", she speaks from the heart, "If I did love you in my master's flame…" Unfortunately, this makes Olivia fall in love with her.

Yet during this first meeting Viola is using language that hints she is a woman. "I am not that I play." To Olivia, this may seem like Cesario is claiming he's not what he appears to