If you read a lot of business media, it seems like every time you open your Facebook or Twitter, you see headlines that say things like "10 Words That Make You Sound Incredibly Stupid" or "15 Reasons Your Co-Workers Think You're the Worst." These pieces usually instruct you to strike regionalisms from your vocabulary or stop saying certain phrases. These articles certainly have validity, but should be read wisely. If used incorrectly, advice like this can cause you to become an inauthentic robot, which is not conducive to doing your best work.
In my industry, it's well understood that conversation dos and don'ts are never black and white. I run a publicity firm and value my publicists' unique personalities, speech patterns, and points of view. I don't want them to sound collegiate all the time - they have to write in many different styles. It's actually imperative that they do because each platform has a very specific target demographic, with their own interests, backgrounds, and values. This, of course, informs the way they speak; a successful publicist must accommodate that.
On any given day they could be pitching to both CNN and Teen Vogue - which have two very different conversation styles. You wouldn't usually use pop culture references or slang in a pitch to CNN as you might for Teen Vogue; then again, you wouldn't pitch to Teen Vogue with a neutral sounding "news" voice as you might with CNN. In fact, the way I'm writing this article right now is far too conversational for CNN!
In public relations, you must resonate with the audience by essentially becoming them. The same is true for all successful businesses who must engage their target customers. And businesses are an extension of the people who operate them, which is why having a phenomenal company culture is crucial.
Assuming you work very hard and are not rude, insensitive, or offensive, if you feel you must significantly change the way you speak and act to fit into your company's culture, then perhaps you are in the wrong company. Don't be a watered down version of yourself. If your restrictive surroundings are causing you to lose your own personal / professional magic, it's time to go.
We so often make professional choices based on money or prestige - but not for joy. There's no reason why you can't have all of those things. Obviously when you're working for a brand - you must represent them. The best way to do this is to align yourself with a company culture that you fit right into. When you are happy and able to be yourself at your job, you will do much better work. The basis of a very worthy New Year's Resolution.