On an app
She asks "bạn ở Việt Nam lâu chưa?".
The line for this moment
I've been in Vietnam for three years now, in Saigon.
The Vietnamese for it, how it sounds to an English speaker, why it works here and not elsewhere, and what she is likely to say back with what to do next: that is what the pack opens, for this line and the others like it.