It may also be true that speech that inflicts harm on oneself is not Right Speech, ie "because of my illness, I have no intention of being a stellar employee," or, "you the interviewer, you, Sir, are profoundly ugly and I'm afraid if I worked here I would stare at that wart on your nose all day." I think there's a limit as to how much negative self disclosure is necessary. We all have limitations. I do feel that the intention of Right Speech starts with ourselves, and this kind of speech need not be self ruinous speech.
Put your best foot forward. Be honest, but don't shoot yourself in that same foot. Get the job, and then surprise yourself later when you win 'employee of the year' despite your limitations. Again, we all have limitations and its incumbent upon ourselves to be thankful for the inspiration these limitations provide our practice. http://www.accesstoinsight.org/lib/auth ... peech.html
Notice the focus on intent: this is where the practice of right speech intersects with the training of the mind. Before you speak, you focus on why you want to speak. This helps get you in touch with all the machinations taking place in the committee of voices running your mind. If you see any unskillful motives lurking behind the committee's decisions, you veto them. As a result, you become more aware of yourself, more honest with yourself, more firm with yourself. You also save yourself from saying things that you'll later regret.