guidelines/style.md.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
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
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”
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
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
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”
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
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.
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
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
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
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
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
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
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
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
- 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
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
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: ♯ ♭ ♮
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
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
- 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
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
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
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
- 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
- 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
- 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
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.nothingPlannedLongis built this way.
STY-29 · What travels, and what stays
- 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
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
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
“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.” |
| 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.