When you enter a chat conversation with a pal, you'll see a green menu bar below.
They consist of four buttons:
Text Mode (Keyboard Icon)
Text mode lets you send text messages and emoticons to your pals.
Voice Mode (Microphone Icon)
Voice mode lets you record and send audio messages to your pals.
Phrasebook Mode (Book Icon)
Phrasebook mode guides you to learn and speak a language through everyday words and phrases, especially if you're not familiar with it.
Media Mode (Plus Icon)
Media mode lets you send or take pictures and send them to your pals.