Uomihime is very quiet, but can speak. Because of her large eyes and lack of blinking, one cannot tell if she is awake or asleep. She explains that Mikotsuhime and her are two in one, if she's asleep, Mikotsuhime cannot be awaken. When she sleeps, Jiiya talks for her.

For more information on this character, you can check out the wiki page: Uomihime

If you'd like context for the audition lines, you can use this website to find the lines listed. The chapter that the lines appear in will be listed with the line. 

https://ww3.mangafox.online/wadanohara-and-the-great-blue-sea/vol-1-chapter-0-450172719097087