Optimizing the max-languages build’s combat ability

This answer about maximizing the languages you can learn points out that you can use downtime to keep learning languages, but if you aren’t going to do that there’s a particular build suggested for maximizing them. That got me thinking: how would it be to actually play such a character? Obviously, you know basically every language in the game, without magic, which is awesome, but in most campaigns language only plays a relatively minor role. Even in campaigns where it plays a major role, there are plenty of situations that care not one whit for your language skills.

The big one is combat. There may be a few combat options (taunts, impromptu negotiation, etc) that your languages help with, but for the most part they don’t. So the question becomes, if you’ve devoted so much to learning so many languages, how can you best leverage whatever else you’re getting along with those languages?

So then, the question is, supposing that by 20th level, you had

  • The half-elf race

  • The acolyte background

  • The Linguist feat

  • 14 levels in ranger

  • 1 level in cleric (Knowledge Domain)

  • 3 levels in mastermind rogue

  • 1 level in druid

Leaving you with 1 class level and at least 2 feats open. How do you maximize this character’s contribution to combat?

This is not the same as maximizing damage per se, though that is surely the typical way to contribute to a combat. But other approaches to contributing—battlefield control, buffs or debuffs, healing—are valid too, so long as they come out of those class levels.

In short, your goal here is to answer “How can we best justify these choices of race, background, feat, and class levels from a combat perspective, rather than doing it just for the languages?” A good answer will demonstrate that they are leveraging those options well. A better answer will discuss how to level the character and progress towards that point. The best answer will not only do that, but also integrate the languages learned into combat—but it still has to be good, not just for the sake of utilizing the languages.