Valerie wants to know if there's any good Walkie Talkie apps for smartphones. Leo says that feature was killed with the smartphone, but Voxer is one that still does it. It even works with the Apple Watch. It's been superceeded with Facebook Messenger and Apple Messages since you can just send audio recordings there now as well. Everyone in the chatroom says Facebook Messenger is the way to go. The downside is that everyone has to use the same one.
TiKL, iPTT, and HeyTell are more options. walkietalkieguide.com has reviews of the big walkie-talkie apps. Valerie could also go to alternativeto.net and search "Voxer," and it will give her many more options to try.