I'm not finding the answer to this on the internet after searching.
When writing dialogue, do you use capital letters to spell out words?
Jamie said, "I said P-L-E-A-S-E please, and don't you forget it!"
Or should it be lower-case?
Jamie said, "I said p-l-e-a-s-e please, and don't you forget it!"
Whether in dialogue or not, proper naming of a single letter of the alphabet varies by style guide. Options include uppercase, lowercase, in quotes, bold, or italics:
As for separators for a word spelled out in dialogue, most style guides are consistent with the CMOS recommendation: Use hyphens (-) not em dashes (—) or en dashes (–):
Hyphens are used to separate letters when a word is spelled out letter by letter in dialogue...
Style guides are NOT consistent about whether to use uppercase, lowercase, or italics for full words spelled out in dialogue. This CMOS example for dialogue recommends using lowercase, no italics:
“My name is Phyllis; that’s p-h-y-l-l-i-s.”
Grammarist also says to use lowercase:
Add a hyphen letter by letter if you’re trying to explain or show how to spell out a word. For example: The correct spelling of “chiaroscurist” is c-h-i-a-r-o-s-c-u-r-i-s-t.
The sole Wikipedia example says to use uppercase:
word would be W-O-R-D
Let's see what AI/ML suggests, as a last resort. Natural Language Processing (NLP) can be used to correct capitalization of uncased or poorly capitalized text, given current English usage. Feeding OP's example,
Jamie said, "I said p-l-e-a-s-e please, and don't you forget it!"
into this NLP sentence case converter (it does true casing) produced the following corrected version:
Jamie said, “I said P-L-E-A-S-E and don’t you forget it!”
I recommend using uppercase, no italics, after careful consideration of Aretha Franklin's excellent example:
What you want, baby, I got it.
What you need, do you know I got it?
All I'm askin' is for a little respect when you come home.
(Just a little bit) Baby
(Just a little bit) When you get home
(Just a little bit) Mister
(Just a little bit)R-E-S-P-E-C-T, find out what it means to me.
R-E-S-P-E-C-T, take care of TCB.
Oh (sock it to me, sock it to me, sock it to me, sock it to me)
... A little respect (just a little bit)
I get tired (just a little bit)
... (Re, re, re, re) 'spect
Or you might walk in (respect, just a little bit)
And find out I'm gone (just a little bit)
I got to have a little respect...
Very few of the of style guides I consulted offer advice on punctuating words intended to be read phonetically letter by letter.
From The Chicago Manual of Style, sixteenth edition (2010):
6.77 Hyphens as separators. A hyphen is used to separate numbers that are not inclusive such as telephone, social security numbers, and ISBNs. ... It is also used to separate letters when a word is spelled out letter by letter, in dialogue, in reference to American Sign Language, and elsewhere.
[Relevant examples:]
"My name is Phyllis; that's p-h-y-l-l-i-s."
A proficient signer can fingerspell C-O-L-O-R-A-D-O in less than two seconds.
So Chicago is firm on the hyphens but flimsy on uppercase versus lowercase letters.
Webster's Standard American Style Manual (1985) goes all-in for lowercase:
4. Hyphens indicate a word spelled out letter by letter.
p-r-o-b-a-t-i-o-n
But The Oxford Guide to Style (2002)—which doesn't address the question of how to represent a word that is being spelled out letter by letter—offers advice on a related question that indicates why a lowercase treatment is potentially problematic:
Use hyphens to indicate stammering, paused, or intermittent speech:
[Relevant example:]
The bell went r-r-r-r-r-i-n-g-g! and then fell silent.
Of course, if Oxford's example had used all caps instead of lowercase, the situation would be just as potentially problematic (but louder):
The bell went R-R-R-R-R-I-N-G-G! and then fell silent.
In many instances, however, loudness is not a factor:
Are you saying r-a-i-s-e or r-a-z-e?
And in those instances I see a minor advantage in avoiding the drawl interpretation by using all caps:
Are you saying R-A-I-S-E or R-A-Z-E?
An alternative (used on the record cover for Tammy Wynette's classic song "D.I.V.O.R.C.E." shown at 0:02) is to replace the hyphens with periods. To my eyes, capital letters separated by periods look less odd than lowercase letters separated by periods. I notice, however, that whoever transcribed the lyrics for that YouTube posting consistently used all caps and hyphens to spell out the words that Tammy and her ex-mate don't want little J-O-E to understand. This choice is evidently quite common, although it is by no means universal, as the split examples in Chicago indicate.
Growing up in the UK whenever I saw this in books, it was always uppercase letters inside speech marks to indicate someone spelling out a word. However, given the way uppercase text is used in messaging and email to indicate shouting these days, I wonder whether usage will change in future. So I would be inclined to use lowercase or sentence casing if I were writing a contemporary novel and did not wish to imply emphasis or shouting of the letters.
Whether in dialogue or not, when naming a letter of the alphabet we write it in upper-case. As far as I know this is so in all languages that use the Roman alphabet.
In situations where one can typographically distinguish the letters being spelled out, lowercase letters would often be better than uppercase. Writing about a and b may be nicer than talking about "a" and "b", or A and B. On the other hand, if text will be transported through a medium that might not preserve italics, then writing about a and b will be less clear than if the text were written in upper case. On the flip side, if one can't represent italics, talking about I and its relationship to J may be less clear than talking about i and its relationship to j.
It's important to note that many journalistic style guides are designed to minimize the amount of work that an editor would need to do with a story prior to publication, even when the publication medium has various technical limitations. If stories use "a" and "b", regardless of whether the medium could support italics, then it won't require rework. If stories use a and b, however, then editors whose media can't support italics would need to edit them to remove quotes.
Another related issue is that some style guides may treat clarity as less important than the avoidance of being wrong. If a piece of text could have two different meanings in the absence of typographical distinctions, and someone preparing the text for publication can't tell which is meant, having that person indicate typographically what they think the text means would risk having the person be wrong. If instead the text on the page is ambiguous, then readers may be confused, but the editor won't be wrong.
