Keyword Set Building
Adapting your app to a country and its language. This means not only content and video translation, but also adjusting to habits, timezone (e.g. for notifications), skin or body types, collocations, and even colors that are used in that country. You will have different semantic cores for each country where you've localized your app.
The App Store supports 155 countries and 40 languages. The most popular are English, European Spanish, French, German, European Portuguese, Chinese, Korean, Japanese, Russian, Latin American Spanish, and Brazilian Portuguese.
Note that US, UK, Canadian and Australian English will have different popular keywords, so you'll need specific semantic cores for each of them.
Google Play supports 137 countries and 47 languages. English languages for the US and the UK are also separated.