Well-spoken
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Lawyers who hide behind legal jargon may be quite competent, but they may also be hiding their incompetence behind a lot of words that non-lawyers and other normal people would never use in ordinary conversation. If a lawyer cannot explain legal concepts to you in language that you can readily understand, it is likely that he does not understand it very well, himself.
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Lawyers often need to use jargon in court, when dealing with other judges or other lawyers; there is rarely a need to do so with a client.