Missions to Unreached Language Groups

Why should going to unreached language groups still be a priority? 

So sometimes I get the question about how the world is getting smaller, people are moving to more urban centers: is missions to remote people groups, to distant more rural environments? Is that still viable? And I would say, yes. I would measure it not necessarily by geography. There's sometimes a movement to go well, let's look at the land, and let's look at the city, let's capture the city first, and I would say let's capture the languages first. By God's grace, the language that is spoken most in the world, has most speakers of it, English, has many translations, it has many churches. And then there's churches by God's grace in Mandarin, but there's not enough. There's churches in Hindi, but there's not enough. But to find the languages, I think that's distinctly Pauline. While there is an urban versus rural kind of paradigm there, what language do they speak? I think that's something that we see throughout scripture and I would I would tend to measure that question more by language than by geography.