They wouldn't speak in MSA. Except in contrived settings, no two people would ever exclusively converse in MSA. In your example, they would meet one another ha

They wouldn't speak in MSA. Except in contrived settings, no two people would ever exclusively converse in MSA. In your example, they would meet one another halfway as you said. One would speak slower and substitute MSA words for colloquial ones here and there. Also, MSA is not like Latin in that it's exclusively written. It's spoken in various official scenarios, e.g. news broadcasts and speeches. I'm unsure what the future of it will be. I used to be pessimistic, but now with the shared widespread access to the Internet (blogs, YouTube), the Arab world will need a lingua franca again.