The languageadapter software allows you to manage translations for websites as packages. Instead of including texts directly in the scripts, placeholders are used, which languageadapter then replaces with the corresponding translation. The principle works similarly to translations for Android native apps. LanguageAdapter implements this functionality in PHP and provides additional support such as automatic detection of which language is best suited for the requesting client, support for country-specific language versions (e.g. en-US, will downgrade to en if en-US is not available) and a fallback language.
For technical details please see the documentation on GitHub
LanguageAdapter code example