How Arpezia writes it down.

Eight rules, side by side

The guide

Applies to the app, public websites, help center, email, notifications, social, and sales material. Internal docs follow punctuation, spelling, and the word list.

Punctuation

STY-01 · Use the Oxford comma

Readable · Checkable

In a list of three or more items, put a comma before the final “and” or “or.”

• Do: The Tuner, Metronome, Tone Generator, and Tone Meter stay free.

• Don’t: The Tuner, Metronome, Tone Generator and Tone Meter stay free.

• Why: it removes the guesswork about where one item ends, which matters most for young and new readers. Our lists name features and prices, so ambiguity costs trust.

• Today: the app already does this in every list we checked (43 strings).

STY-02 · No em dashes or en dashes

Readable · Checkable

Use a comma, a colon, parentheses, or a new sentence instead. Hyphens are fine inside compound words (“long-tone study,” “7-day trial”).

• Do: Rest between steps. Your lips need it.

• Don’t: Rest between steps — your lips need it.

• Why: a dash usually hides a second sentence. Two short sentences read better at every age.

STY-03 · Ranges use “to”

Readable · Translatable · Checkable

Write every range with the word “to,” including note ranges, times, prices, and page numbers in references.

• Do: Play G4 to C6. Takes 5 to 10 minutes.

• Don’t: Play G4-C6. Takes 5-10 minutes.

• Why: “G4-C6” can read as a subtraction or a code. “To” reads aloud correctly, including in screen readers.

STY-04 · Exclamation marks follow the voice, with fixed limits

Real celebrations · Helpful · Checkable

At most one per message. None in errors, warnings, billing, privacy, consent, or proof-mode copy, in any voice direction. Never two in a row.

• Do: 14 days in a row! A little every day is how progress happens.

• Don’t: Payment failed! Please try again!!

• Why: an exclamation mark is a celebration. It only means something if it’s saved for real ones.

STY-05 · Curly quotes and apostrophes

Readable · Checkable

Use curly quotation marks and apostrophes (“ ” ’) in everything a person reads. Straight ones belong in code. Periods and commas go inside closing quotation marks, American style.

• Do: Delete “Morning warm-up”? Your practice history stays.

• Don’t: Delete "Morning warm-up"? Your practice history stays.

• Why: typographic quotes read as finished and trustworthy. Nobody has to type them: a build step can convert them.

• Today: most app strings use straight quotes (107 strings). This is a one-time conversion, not a rewrite.

STY-06 · One ellipsis character, only for “still going”

One word · Checkable

Use the single character “…”, never three periods. Use it only for loading states and for placeholders that invite typing. Never use it for suspense or trailing off.

• Do: Loading your library…

• Don’t: Loading... / Your streak is about to end...

• Today: 29 strings use “…” and 23 use “...”.

STY-07 · Periods on sentences, not on labels

Readable

Full sentences end with a period, including one-sentence hints, errors, and empty states. Headings, buttons, tabs, labels, and single-phrase list items don’t.

• Do: Button: Start practice · Hint: Hold one note for 3 seconds.

• Don’t: Button: Start practice. · Hint: Hold one note for 3 seconds

STY-08 · Write “and,” not “&”. Skip semicolons.

Readable · Translatable · Checkable

Use “&” only inside a proper name that uses it. Replace a semicolon with a period and a new sentence. Use parentheses rarely, and never for information people need, because skimmers and young readers skip them.

• Do: Plans and routines

• Don’t: Plans & routines; exercises too

STY-09 · Colons introduce, lowercase follows

Readable

A colon introduces a list, an explanation, or a value. Keep lowercase after it unless a proper noun or a full sentence follows. Headings and buttons never end with a colon.

• Do: Today: 3 steps, about 23 minutes.

• Don’t: Today’s plan:

Capitals

STY-10 · Sentence case, everywhere

Readable · Translatable · Checkable

Headings, buttons, tabs, menu items, page titles, email subjects, and social headlines capitalize only the first word and proper nouns.

• Do: Create a routine · From the method books

• Don’t: Create A Routine · From The Method Books

• Why: sentence case reads like speech and is faster to scan. Most languages we translate into don’t use title case at all.

STY-11 · Capitalize names, not kinds of things

One word

Capitalize the named tools, tiers, and branded features, because they are things you can keep or buy: Tuner, Metronome, Tone Generator, Tone Meter, Plus, Studio, Institution, Inner Circle, and The Musicians’ Room. Lowercase the kinds of content: routine, exercise, lesson, song, plan, goal, badge, streak, challenge.

• Do: Open the Tone Meter to see your sound on the tone map. Pick a routine.

• Don’t: Open the tone meter to see your sound on the Tone Map. Pick a Routine.

• Today: the same tool appears as “Tone meter,” “Tone Meter,” “tone meter,” and “tone map.”

STY-12 · Arpezia, and the trademark symbol

One word · Checkable

Always “Arpezia,” capital A, never possessive in headlines. On public pages, use ™ on the first prominent mention and in the legal footer. Never use ™ in the app, email body text, or social posts. The retired codename never appears in public.

• Do: Arpezia™ plans your practice. (first use, website)

• Don’t: ARPEZIA’s plans · arpezia · Arpezia™ on every mention

STY-13 · Never type in all caps

Readable · Translatable · Checkable

If a design wants capitals (eyebrows, the logo lockup), the styling makes them. The text stays in normal case. The one exception is the lockup mantra, UNDERSTAND. CREATE. EVOLVE.

• Why: some screen readers spell out capitalized words letter by letter, and translators need the real case.

Numbers, time, units, and money

STY-14 · Digits when you’re counting

Readable · Honest numbers · Checkable

Use digits for every count, including 1 to 9. Use words only when the number isn’t a count, as in the brand line “one note at a time.” Rewrite a sentence rather than start it with a number in long-form copy.

• Do: 3 steps · 5 days ago · 1 badge

• Don’t: Three steps · five days ago · one badge

• Why: digits scan fastest, and every age reads them.

STY-15 · Round at the screen

Honest numbers

Whole minutes, whole cents, whole percentages. Say “about” when rounding hides something that matters. Never round in the flattering direction.

• Do: about 23 minutes · 12 cents sharp · 60%

• Don’t: 23.4 minutes · 11.8 cents · 59.6%

STY-16 · Units: spell out, then shorten

Readable · One word · Checkable

• Minutes and seconds: spell out in sentences (“23 minutes”). Use “min” and “sec” only in tight spaces like pills and cards.
• Tempo: “beats per minute” the first time on a screen a young player might see, then “BPM” in capitals. Never “bpm.”
• Cents: always spelled out. Explain once where it first appears: “cents (100 cents is one half step).”
• Hertz: “440 Hz,” with a space.
• Percent: the % sign, applied by the number formatter so each language gets its own spacing.

• Today: 10 strings use “BPM” and 5 use “bpm.”

STY-17 · Dates, times, and money come from the formatters

Translatable · Checkable

In the app, every date, time, number, and price goes through formatDate, formatDateTime, formatRelativeTime, or formatNumber. Never write them by hand. Use relative time for the recent past (“5 days ago”) and a named day for deadlines (“until Friday, October 2”), never a countdown timer.

• Do: $7.99 a month · $59 a year · Free

• Don’t: $7.99/mo · $59/yr · $0

• Why: named deadlines inform without pressure. “/mo” is fine in a pricing table’s column header, not in sentences.

Music in text

STY-18 · Note names carry their octave

Readable · One word

Write notes in scientific pitch notation: letter, accidental, octave number. Middle C is C4. Where octave numbers first appear for a player, explain them once: “C4 is middle C.”

• Do: Play F♯3 to C6.

• Don’t: Play low F sharp to high C.

STY-19 · Real accidentals: ♯ ♭ ♮

Readable · Checkable

Use the real symbols in everything a person reads. “#” and “b” belong in code and data only (fingerings.js keeps its keys). Input fields accept both and show the symbol.

• Do: Lowest note (for example, F♯3) · B♭ trumpet

• Don’t: Lowest note (e.g. F#3) · Bb trumpet

• Today: the goals screen shows “F#3” in two strings. The fingering chart already writes “B♭ trumpet.”

STY-20 · Say which pitch when it could be read two ways

Helpful

Trumpet and many other brass and woodwind instruments are transposing. When a pitch could mean written or concert pitch, say which.

• Do: Tune to concert B♭ (written C4 on B♭ trumpet).

• Don’t: Tune to B♭.

STY-21 · Titles, people, and terms

Claims earned · Readable

• Method books and pieces: italic in long-form and on the website (Technical Studies). In the app, plain text with the author and year above the title.
• Study numbers: “Technical Study No. 2.”
• Reference players: full name on first mention, and always “modeled from recordings.” Never words that suggest endorsement (“Chet Baker recommends”).
• Instruments: lowercase (“trumpet,” “flugelhorn”), with the key when it matters (“B♭ trumpet”).
• Italian terms: player’s word first, the term in parentheses on first use: “smooth and connected (legato).” No italics in the app.

Interface, email, and social

STY-22 · Buttons name the outcome

Helpful · Checkable

Verb first, 1 to 3 words, sentence case, no period. Pair destructive actions with a named way out. Never “OK,” “Submit,” or “Yes/No.”

• Do: Delete routine · Keep routine

• Don’t: OK · Cancel

STY-23 · Errors: what happened, why, what to do

Helpful · Checkable

Three parts, in that order. No “error,” “invalid,” “failed,” “oops,” “sorry,” or “please.” No developer words (stack trace, console, IndexedDB).

• Do: We couldn’t hear a steady note. Move a little closer and hold one note for 3 seconds.

• Don’t: Error: invalid input. Please try again.

STY-24 · Placeholders are examples, links say where they go

Readable · Checkable

A placeholder shows an example and disappears, so it never holds the only instruction. Link text names its destination. Never “click here” or “learn more” alone.

• Do: Label: Email · Placeholder: you@example.com · Link: Read about our method

• Don’t: Placeholder: Enter your email to continue · Link: Click here

STY-25 · Email and notifications

Right reader · Real celebrations

• Subject lines: sentence case, 50 characters or fewer, one ask. No all caps, no fake urgency (“Last chance!”).
• Push notifications: 100 characters or fewer. They inform. They never threaten a streak.
• Anything about a player under 13 goes to the parent or guardian, written to the adult.

STY-26 · Social posts

Readable · Claims earned

• Hashtags in capitalized words (#BrassPractice) so screen readers say them correctly. 3 at most.
• Emoji follow the chosen voice direction. Never in place of a word.
• Every image has alt text. Every research claim links to the method page.

Inclusive and accessible writing

STY-27 · Write for every age and every body

Right reader · Readable · Checkable

• Use “they” for a person whose pronouns you don’t know. Sample names come from many cultures.
• Don’t assume an age. No “your commute” or “your kids,” and no “for kids” talk.
• Don’t judge difficulty: no “easy,” “simple,” “just,” or “obviously.”
• Never point by color or position alone (“the green button,” “on the right”).
• No medical claims about breathing, embouchure, or health.

Writing for translation

STY-28 · Whole sentences, one string

Translatable · Checkable

Never build a sentence from pieces. Put variables inside one string with named placeholders. Use the plural rules in the i18n library, never “(s).”

• Do: Nothing planned for today. Pick a quick start below, or build your own plan.

• Don’t: “Nothing planned for today. Pick a quick-start below, or” + \[button\]

• Today: dashboards.nothingPlannedLong is built this way.

STY-29 · What travels, and what stays

Translatable · Claims earned

• Never translated: Arpezia, reference player names, method-book titles, and author names.
• Translated with care: tier and feature names, once each language’s glossary is approved.
• Localized, not translated: punctuation (the Oxford comma is English only), quotation marks, number and date formats.
• Leave room: text grows up to 30% in translation. No idioms or puns in the app. No text inside images.

Citations and claims

STY-30 · Cite in the sentence, list in full below

Claims earned

In running text, put authors and year in parentheses, Chicago author-date style, with no comma before the year. List full references at the end of the page, with a link.

• Do: (Duke, Simmons, and Cash 2009)

• Don’t: (Duke et al., 2009) · “studies show” with no source

• Why: naming all three authors keeps the Oxford comma rule, and a reader can find the paper from the sentence alone.

STY-31 · Say who was studied, in their words

Claims earned · Honest numbers

Every research claim names who was studied and repeats numbers as the study reports them. Never round a finding up, and never turn one study into “research proves.”

• Do: In a study of 17 advanced pianists, practice strategy predicted next-day accuracy better than practice time.

• Don’t: Science proves practice time doesn’t matter.

STY-32 · Claim words, by strength

Claims earned · Checkable

“We believe” for the Why. “Built on” or “designed around” for method claims with a source. “Arpezia measures” only for what the product does today. Outcome words (“improves,” “results”) only with Arpezia’s own published data. Never: “proven,” “guaranteed,” “scientifically designed,” “clinically,” “10,000 hours.”

Word list

One word per thing, in the nav, headings, buttons, emails, and posts.

Use	Not	Notes
Arpezia	the retired codename, “the app”	Name the product when the sentence needs a subject.
player	user, learner, customer	The person who plays. “Student” only when a teacher is in the picture. Never “user” in anything a person reads.
teacher	instructor, educator (in UI)	“Music educator” is fine in proof mode and school sales.
parent or guardian	parent (alone), adult	Consent copy always uses the full phrase and speaks to the adult.
free trial	free week, trial period, demo	“7-day free trial” when the length matters. One name for the one trial, so nobody wonders whether a “free week” is a separate offer.
sign in, sign out, create account	log in, login (as a verb), sign up (as a button)	“Sign-in” with a hyphen only as a noun or adjective (“sign-in link”).
The Musicians’ Room	Conservatory, Lumina, music room	Renamed September 26, 2026 (ADR-0111). Capital T at the start of a sentence or heading, lowercase “the” mid-sentence. Its invitation line is “Pull up a chair.”
email	e-mail, mail
choose, start, open	click, tap, select (for on-screen controls)	Say what the person does to the content, not to the device. “Press” is for physical keys and press-and-hold.
microphone	mike	“Microphone” in permission and privacy copy. “Mic” is allowed in short labels.
Tone Meter, tone map	tone meter (lowercase), Tone Map	The Tone Meter is the tool. The tone map is the brightness and richness chart it draws.
Tone Generator	Drone (as the tool’s name), Tone Gen	The tool’s name, decided September 30, 2026. “Drone” stays as the music word for the held pitch it plays: “The Tone Generator plays a drone to tune against.”
Tuner, Metronome, Tone Generator, and Tone Meter	any other order	The four free tools, always listed in this order.
routine, exercise, lesson, song, plan, goal	workout, drill set, track	Lowercase in sentences. These are the six content words.
badge, streak, challenge, leaderboard	achievement, trophy, points, XP, level	Today the badges screen says “No achievements yet.” It should say badges.
outline	skeleton	A copyrighted method book shown as structure only. Tooltip explains the copyright.
practice (noun and verb)	workout, training, grind	“Session” only for a timed run in the practice player.
reference player	celebrity, pro, idol, famous player (in UI)	Always paired with “modeled from recordings” on first mention.
long tone, lip slur	sustained tone exercise, embouchure flexibility variant	Hyphenate only before a noun: “long-tone study.”

Checklist

The rules a script or AI reviewer can enforce on every change. Each ID matches a card above, so a flagged string links back to its reason.

ID	Rule	What the check looks for
STY-01	Oxford comma	a list of 3 or more with no comma before and/or
STY-02	No em or en dashes	the characters U+2014 and U+2013 anywhere
STY-03	Ranges use “to”	digit-hyphen-digit, or note-hyphen-note like G4-C6
STY-04	Exclamation limits	more than one “!” per string; any “!” in error, billing, privacy, or consent keys
STY-05	Curly quotes	straight ' or " in reader-facing text
STY-06	One ellipsis character	three periods in a row
STY-08	“And,” not “&”	a space-ampersand-space outside proper names
STY-10	Sentence case	headings and buttons with 2 or more capitalized words that are not names on the word list
STY-12, 13	Brand name and all caps	the retired codename; lowercase “arpezia” in copy; words in all caps
STY-14, 16	Digits and units	number words before a noun; lowercase “bpm”
STY-17	Formatters only	Intl or toLocale calls in components
STY-19	Real accidentals	a note letter followed by # or b and an octave digit
STY-22, 23, 24	Buttons, errors, links	OK, Submit, click here, learn more, oops, sorry, please, invalid
Word list	One word per thing	every “Not” entry in the word list
STY-27	Inclusive words	easy, simple, just, obviously
STY-28	Whole sentences	strings ending in “or,” “and,” or a comma; “(s)”
STY-32	Claim words	proven, guaranteed, scientifically, clinically

Decisions needed

Choose over select?

Microsoft’s guide says “select.” This draft says “choose,” because an 8-year-old reads it more easily and it works on every device. Keep it?

Curly quote conversion

Converting about 107 existing strings is one scripted change plus a check that keeps them curly. Worth doing with the first rewrite pass?

Tier names in translation

Do Plus, Studio, and Institution stay in English in every language, like Arpezia, or get translated?

“Today” notes count strings in the app’s English locale file on September 30, 2026. This guide follows its own rules. If you find a place where it doesn’t, that’s a bug in the guide.