This app was mentioned in 4 comments, with an average of 0.75 upvotes
there an app on the google play store (dont know about IOS version) where you can listen to all the lines, I THINK its called LoL voices with the freljord banner as an icon. EDIT: i found it: https://play.google.com/store/apps/details?id=com.sysoft.voicesoflol&hl=fr
Or you can download Voices of LoL. I hope you use Android and suits for the app.
edit: and found this for IOS. Don't have any idea does they patch it.
Also consider that if you want to keep your app small (less than 500MB), you will need a server to provide downloads for each sound.
I made an app with the voices of every champion and NPC in 16 languages, using a server to allow the users to download the sounds, and all the voices (not sound effects) in the 16 languages are 6GB in total, so you definitively need a client-server structure on the app.
If you want to check it out:
https://play.google.com/store/apps/details?id=com.sysoft.voicesoflol
If you are really interested on creating apps try to avoid using app creation kits and learn from the ground Java, is not that hard.
totally NOT this app https://play.google.com/store/apps/details?id=com.sysoft.voicesoflol
Though the numbers you told does NOT checks out, seems like you're lying somewhere