The gospel has been preached to ALL languages? There are no unreached people-groups? I don’t think so.
Your question reminds me of something a friend of mine told me recently. In her “Bible group” (let’s call it, although it’s not that it’s more a group of friends who gather to talk about how Christ is alive today), one participant was this young man from Japan, who was a co-worker of one of the other participants.
During their discussions about Christ, he was constantly interrupting the conversation to ask about topics like “the Incarnation” and “Ressurection”. It turns out this young man had never heard the Gospel message and was asking out of true ignorance, not malace or critical intent. He was eager to hear the Word.
The point is, he had never heard the Gospel. Sure there are Bibles in Japan, but that isn’t what is only meant by “preaching the Gospel”.
Where has it not been preached? Seriously. There are even bibles in Antarctica.
***I would defer to the experts, folks like Wycliffe Bible Translaters who are focused on the remaining languages to have the bible translated. They seem to think there are still quite a few unreached people groups.