Voice translation is crucial for those moments when you need to talk to someone who speaks a different language. RTranslator is a real-time translation app that makes it easier to speak to someone in a different language.
The conversation mode allows you to translate a conversation in real-time by connecting two or more devices that use the app. If the user accepts your connection request:
When you talk, your phone (or the Bluetooth headset, if connected) will capture the audio. The audio captured will be converted into text and sent to the interlocutor’s phone.
The interlocutors’ phone will translate the text received into his language. The interlocutors’ phone will convert the translated text into audio and will reproduce it from its speaker (or by the Bluetooth headset of the interlocutor, if connected to his phone).
Conversation mode is useful for having a long conversation with someone.

The WalkieTalkie mode is designed for quick conversations, such as asking for information on the street or talking to a shop assistant.
This mode only translates conversations between two people, it doesn’t work with Bluetooth headsets, and you have to talk in turns. It’s not a real simultaneous translation, but it can work with only one phone.
To use RTranslator, you have to configure it. Also, the Google APIs on which the app is based are not free. When you create your account for the first time, you have a $ 300 voucher valid for one year, but after that, the APIs will no longer be free. Read the GitHub page for more details and a tutorial for the configuration.
You can get the app on Google Play.