A stutter can be a powerful rhetorical device, a dramatic and inspiring act of auditory self-flagellation, provided the audience knows beforehand that there are certain words or phrases — tortuous (for you) exercises in elocution — whose pronunciation, aggravated by your labored series of starts and aborted finishes, are the ultimate sign of sincerity; that, by struggling mightily to say the right thing, the atmosphere may grow uncomfortable, witnesses may blush in embarrassment on your behalf and the seconds may seem interminable, as you maintain your composure and exhale, so you may continue or beg the audience’s indulgence — you may thank the listeners for their patience and understanding — while you find a different aphorism and articulate another epigrammatic example of eloquence.
Let the audience know that a lisp or stutter does not mean you will fail or falter.
Make it clear that your difficulty saying specific words — that the interruption of your otherwise mellifluous presentation — is not a verbal admission of guilt, as if the battle to speak the psalms of justice and charity is somehow proof of your own malice and cruelty.
On the contrary, it takes courage to stand before a microphone or a podium, or to approach a jury box without a physical totem for your own distraction, without an object to assuage your anxiety and stabilize your voice, as you attempt to modulate your tone — and as you manage to adjust each octave, lowering or amplifying the words because of the importance of the situation and the suspenseful silence of a particular scenario — in service of a cause greater than yourself.
You already possess the tools, in all their polysyllabic complexity.
Now, finish the job!