While much of elementary is developed in English, there are many users who do not know English or prefer their native language. While putting text into your app, keep the following in mind:

• Make it translatable. Always, always make your text translatable using the built-in methods. It can't be translated if you don't make it translatable. Include punctuation in translatable strings.
• Avoid culture-specific references. Remember that users of another language are going to be using your app. Specific metaphors or references will likely be lost on or downright confusing to other those users. Instead, use universal text.
• Keep differences in mind. Remember that other languages and cultures often use different currencies, date formats, punctuation, and more. Always keep these things in mind when developing your app's text, and use the system-provided methods for translating these items when possible.
• Right-to-left. It's easy to forget about right-to-left (RTL) languages if you're so used to using left-to-right. Make sure your app still works well when used with RTL layouts, and always use RTL-compatible widgets when developing your app.