A poll just released by Harris Interactive shows that employers are less likely to promote a worker who curses. These bosses gave several reasons why. Bad language calls a person's professionalism into question. Employers see such as a self-control problem. They also see it as a lack of maturity and a sign of lower intelligence (via PRNewswire and Careerbuilder.com). The bottom line is that "bad words leave bad impressions" (ibid.).
Certainly, a Christian does not need such a survey and should not be threatened by these findings. The Bible makes speech a basic building block of good influence for those of us who are ambassadors for Christ. Being "sound in speech" puts one "beyond reproach" with "opponents" who may be prone to have something "bad to say about us" (Titus 2:8). Our speech should "always be with grace, as though seasoned with salt" in order to properly "respond to each person" (Colossians 4:6). No "unwholesome word" should "proceed" from our mouths (Ephesians 4:29). Jesus warned that "the mouth speaks out of that which fills the heart" (Matthew 12:34).
What an opportunity God gives Christians in this world to represent Him to them! We should not be most concerned with what monetary value there is in keeping our speech pure and clean, but rather consider above all else the spiritual value! We should not be only concerned with what potentially negative impact bad language may have on a superior, but equally focused on how it impacts peers and subordinates. For good or bad, our language does make a difference. It should reflect truth, honorableness, right, purity, loveliness, and good reputation for these should be that upon which we are reflecting (Philippians 4:8). Whether or not it wins you an earthly promotion, guard your speech out of interest for that spiritual promotion!