"Lark" is a multi-user (2000), cross-regional, while online, to voice / video calls in real-time learning, social, tools APP. Usage scenarios include conference calling, voice chat rooms, discussion groups, voice, speech class ...
In the process you and your partner communicate in doubt, direct voice dialogue is one of the fastest way to solve problems. Chat beat codeword, and the most emotional, most can enhance mutual trust. "Call" would be a good choice, and quickly try it ...