A Madrigal of Clarity

I was summoned for jury duty recently, but it conflicted with travel plans. I just got the following letter from the Sheriff's office:

Dear [you],
Re: Jury Duty

You have requested to be excused from jury duty.

You are excused.

Therefore you do not have to appear on [redacted date] for jury selection.

Yours truly,
[et cetera]

I am kinda in love with this letter. Talk about ascribing to the principle of "omit needless words"! This is clear and complete, and a third grader could understand it.

It reminds me of something an American friend, who immigrated to Canada, but who had also worked with new immigrants in the States, once noted: You can tell a lot about the mindset you're up against by the language that gets used on you.

If you want to immigrate to Canada, the forms you need to fill out are written in fifth-grade comprehension level English (or French.)

If you want to immigrate to the United States, the forms you need to fill out are written in legalese.

Guess which country is more open to the idea of you moving in.

I read Tara Road by Maeve Binchy recently, and I was struck by how effectively the author communicated her protagonist's turmoil after that character's husband admits he has made a younger woman pregnant and is leaving his wife. Ms. Binchy did it solely by changing the protagonist's voice; a previously bubbly and bumbling personality was abruptly delivering lean, razor-edged dialogue. She didn't sound anything like how she had in the rest of the book, and it worked beautifully. You knew this woman was both shattered by and hostile to the future her husband was forcing upon her.

In your writing, do you ever alter the way a character speaks to betray their mindset? Even beyond changing the rhythm of how they speak in order to show emotion, do you change their voice?