AbdulAlhazred
Legend
That's a great game! I like that kind of stuff. The issue is, you're not really giving up much or anything thereof by playing a combat-focused character. There are several low-level items in AV alone (for instance) that pretty much make linguist superfluous. For that matter, many characters get to pick a free language; you can often cover most languages without linguist.
Any DM I know, if you dramatically try to save the day by communicating and roleplaying, they're going to let you do that regardless of minor details like feats that you have. A good bit of roleplaying is going to be worth more that any stat on paper - and you can get those stats cheaply too.
Finally in which game would failing to know the language be "you die (no save)?" Seriously, that's just a pretty killer DM.
I'm not saying roleplaying's worthless and combat is all that counts, I'm just trying to be honest here and my impression is that for roleplay stats&feats rarely matter, and so you should pick most stats&feats for combat purposes. It's an intentional design choice to make it hard to trade-off combat prowess for role-playing skill. WotC succeeded; it's generally unwise to try and gain out-of-combat advantage with combat-oriented stats and vice versa.
This isn't an absolute, but it's common enough to conclude a general principle.
Linguist is a trap ;-).
Maybe you need to play with a higher grade of DMs, lol. I don't mean that too seriously but essentially this argument is the same as someone assuming that if they have a character weak in combat ability that the DM will be nice to them and only throw weaker monsters at them. By that logic Weapon Expertise is no more valuable than Linguist and in fact it shouldn't matter at all what feats you take because the DM will never challenge your character to be the best, he'll just let you slide with whatever you have.
More realistically of course DMs generally aren't interested in playing out doomsday scenarios with their players where lack of a specific skill, feat, or level of combat prowess spells instant and irrevocable failure. Instead DMs generally throw a mix of challenges at a party where in some cases one thing is helpful and in another case a different thing is helpful.
The linguist may avoid combat and gain treasure through other means at times. The combat specialist will likely slog through the combat encounter and may achieve the same (or better, or worse) rewards in the long run. Thus we see that Weapon Expertise, Linguist, Skill Focus, a high starting primary ability score, a more diverse set of ability scores, etc are all essentially equally viable options in principle. Some games will in fact value one or another more or less in all probability but a really good DM will not reward one path excessively and punish others unless his players are only interested in one subset of the game.