Web and mobile applications today should be designed and built from the ground up to support international markets, unless there is a strong business case to restrict them to a single market.
The availability of tools and frameworks to provide your application with international support (including multiple languages, currencies, locales, etc.) lowers the barrier for application development teams, but the technology build is only part of the challenge of supporting international markets.
In Part 1 of this two part post, we look at the basics if international software, and how to plan your project to best support the demands of international applications.