These style guidelines help us construct our content to be clear and consistent. As with everything else we do at Duolingo, user-friendliness is our guiding force. Our grammar and style rules are based on usability, not always what's proper.
Numerals
Write all numbers numerically, even numbers under 10. But if a number starts a sentence, spell it out. (If it's a really big number like 5,678, rewrite the sentence so it doesn't start with the number.)
If the number is over 999, include a comma. But don't include a comma for XP or other currency totals in the product.
Emoji
Emoji are super useful. They convey information. They grab attention. But a little emoji go a long way.
Punctuation
Punctuation marks help us break information into readable chunks. They also dictate the tone of our content! (Like so!) We have some hard-and-fast rules for which punctuation marks we use where....and which we really, really try to avoid.
Punctuation
Periods
Periods go inside quotation marks. Always follow a period with one space, not two.
Punctuation
Dashes
There are three — yes, three — kinds of dashes. We mostly use hyphens and en dashes.
Punctuation
Colons
If the copy following a colon is a fragment, don't capitalize the first word. If it's a complete sentence, capitalize!
Punctuation
Commas
Use the serial comma (a.k.a. Oxford comma).
Punctuation
Ellipses
We don't use ellipses frequently...but when we do, there isn't a space on either side... But if the ellipsis ends the sentence, add a space.
Punctuation
Semicolons
Instead of a semicolon, use an em dash. Even better: Break long, two-part sentences into two simple sentences.
Punctuation
Apostrophes
When a singular word ending in s, x, or z has a possessive, put an s after the apostrophe.
Punctuation
Quotes and quotation marks
Simple rules to get statements right.
Punctuation
Ampersands
Avoid using & to replace "and" in copy. One exception is ads with a low character count — but when there is space to write out "and," it is more user-friendly.
Formatting
Formatting is like visual design for copy. These guidelines aren't grammatical rules, but rather how we treat these situations at Duolingo.
Formatting
Capitalization
We minimize capitalization in an effort to make our product and brand as approachable as possible. That's not to say that everything is lowercase — we do put button copy in ALL CAPS, and most feature names (like Stories) are capitalized.
All list items should be formatted identically. So if one fragment, all fragments. If one sentence, all sentences.
Formatting
Bold
Bold text to refer to UI elements or actions.
Formatting
Italics
Italicize titles of books, magazines, films, and music albums. Put quotation marks around song titles and article titles. (This may never come up, but it's a good rule to know.)
Formatting
URLs and email addresses
Leave off the http:// and www., and put the rest of the URL in lowercase. Put email addresses in all lowercase.
Parts of speech
Welcome to the nitty gritty of grammar! Forget what you learned in school: Every brand has its rules for certain word types. And these are ours.
Parts of speech
Contractions
Contractions are okay and encouraged. Use them when they make a sentence read more naturally. (In some cases, not using contractions is a strong way to get something important across.)
Parts of speech
Conjunctions
It's okay to start a sentence with a conjunction (and, but, or).
Parts of speech
Prepositions
It's okay to end a sentence with a preposition (to, for, of, with, etc.) if it reads more naturally.
Etc.
Guidelines for the miscellaneous characters and symbols that work their way into copy.
Etc.
Phone numbers
Hyphens only, no parentheses.
Etc.
Money
Put the dollar sign or other currency symbol in front of the amount. For even amounts, omit .00. If less than a dollar, write x cents.
Etc.
Percentages
Use the % symbol instead of writing out percent.
Etc.
Time
Write the numeral and then am or pm, with a space between. If the time is on the hour, write it as :00. Midnight and noon are neither am nor pm, so write midnight and noon on their own.
Capitalization
Consult these charts before hitting the Shift key or Caps Lock.
Capitalization
Capitalize
Generally speaking, we capitalize things that are particular to Duolingo, whether that's an achievement name or a feature type.
Capitalization
Don't capitalize
We like to keep headers, subject lines, and most things lowercase to maintain Duolingo's feeling of approachability.