The Localization of Stack Overflow- QCon China 2014

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The Localization Of Marco Cecconi @sklivvz sklivvz@stackoverflow.com

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Who are we?

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561,027,840 pageviews in the last 30 days* (~100% growth year over year) *source: Quantcast

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Why did we want to do this?

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Expert programmers Fluent English EN Stack Overflow

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Expert programmers Fluent English EN Stack Overflow Fluent Portuguese PT Stack Overflow

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Different languages make Different communities

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Expert programmers Stack Overflow

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We want to make the internet a better place for all

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Architectural Requirements

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Easy.

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Easy. Fast.

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Performance is a feature

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1. Allocates two objects per translated string 2. Does a lot of lookups

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1. No allocation (strings are interned) 2. No lookups 3. Not “easy”, not “usable”

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Simplest/easiest possible code

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Simplest/easiest possible code Implementation

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Source Code Compile Time Run Time aspnet_compiler Look Up

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Simplest/easiest possible code Compiled to the equivalent of this

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Source Code Compile Time Run Time extended aspnet_compiler using Roslyn Look Up

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Javascript - No GC pressure so we don’t care about interned strings - Can’t really precompile either - We simply create one set of JS files per language, e.g. “stub.en.js” and “stub.pt.js” - For all that follows, the same APIs are available to Javascript

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Our solution

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API _s(string value) Meaning “Substitute String” _m(string value) Meaning “Substitute Markdown”

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Languages are WEIRD (part 1)

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_s("Hello $name$", new { name = "Marco" }) Hello Marco

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一隻雞兩隻雞

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1 chicken 2 chickens

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Language Name Code Category Examples Rules Chinese zh other 0-999; 1.2... other → everything English en one 1 one → n is 1; other → everything else other 0, 2-999; 1.2, 2.07...

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one 1, 21, 31, 41, 51, 61, 71, 81, 101, 1001, … i % 10 = 1 and i % 100 != 11 few 2~4, 22~24, 32~34, 42~44, 52~54, 62, 102, 1002, … i % 10 = 2..4 and i % 100 != 12..14 many 0, 5~19, 100, 1000, 10000, 100000, 1000000, … i % 10 = 0 or i % 10 = 5..9 or i % 100 = 11..14 other 0.0~1.5, 10.0, 100.0, 1000.0, 10000.0, 100000.0, 1000000.0, … other 0~15, 100, 1000, 10000, 100000, 1000000, … Ukranian!

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Welsh has SIX modes…

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_s(“#num# chickens", new { num = 3 }) 3 chickens

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Behind the scenes All combinations are generated for each language and sent to translators:  For Chinese: “$num:other$ chickens” will be sent  For a 2 mode language: “$num:one$ chickens” and “$num:other$ chickens” will be sent Rules have to be evaluated at runtime to choose the correct translation.

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Languages are WEIRD (part 2)

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10 classes called Class I to Class X and containing all sorts of arbitrary groupings but often characterised as • people, • long objects, • animals, • miscellaneous objects, • large objects and liquids, • small objects, • languages, • pejoratives, • infinitives, • mass nouns Uganda

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_s("Active $~posts$") Attivi _s("Active $~questions$") Attive

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Post Mortem

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Some numbers 700 views localized 100,000 lines of code A lot of javascript A LOT of refactoring/fixing/tech debt repayed Very little performance impact ~6 months of work (team of ~3)

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More numbers Portuguese released Dec. 12 4k Questions 7k Answers 8k Users One of the best performing new communities ever

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Lessons learned

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Never put non-content text data in the DB It’s A Good Thing™ if all the text to be localized is in the views or javascript.

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Never compose sentences in code n==1? "1 unicorn": n.ToString() + " unicorns"

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Never assume anything about the language 10 genders and 6 plurals? REALLY?

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Designing a global application is hard

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Conclusions

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1. It’s possible to internationalize quickly and cheaply, without performance hits. 2. Localization is a surprisingly rich problem. There are many gotchas that can be painful later, like pluralization “bugs”. Fun! 3. Localization is a very healthy choice for Stack Overflow and we hope to provide more and more users with a native interface some day :-)

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Questions? Marco Cecconi @sklivvz sklivvz@stackoverflow.com