To provide translations in other languages (locales), we need to create a strings.xml in a separate folder by the following convention :

res/values-<locale>/strings.xml

An example for the same is given below:

In this example, we have default English strings in the file res/values/strings.xml, French translations are provided in the folder res/values-fr/strings.xml and Japanese translations are provided in the folder res/values-ja/strings.xml

Other translations for other locales can similarly be added to the app.

A complete list of locale codes can be found here : ISO 639 codes

Non-translatable Strings:

Your project may have certain strings that are not to be translated. Strings which are used as keys for SharedPreferences or strings which are used as symbols, fall in this category. These strings should be stored only in the default strings.xml and should be marked with a translatable="false" attribute. e.g.

<string name="pref_widget_display_label_hot">Hot News</string>
<string name="pref_widget_display_key" translatable="false">widget_display</string>
<string name="pref_widget_display_hot" translatable="false">0</string>

This attribute is important because translations are often carried out by professionals who are bilingual. This would allow these persons involved in translations to identify strings which are not to be translated, thus saving time and money.