Document more monolingual formats and template usage (issue #249)

docs/formats.rst

@@ -9,6 +9,21 @@ tested formats.
 
 .. seealso:: `Supported formats in translate-toolkit`_
 
+
+Weblate does support both monolingual and bilingual formats. Bilingual formats
+store two languages in single file - source and translation (typical examples
+is :ref:`gettext`, :ref:`xliff` or :ref:`apple`). On the other side,
+monolingual formats identify the string by ID and each language file contains
+only mapping of those to given language (typically :ref:`aresource`). Some file
+formats are used in both variants, see detailed description below.
+
+For correct use of monolingual files, Weblate requires access to file
+containing complete list of strings to translate with their source - this file
+is called :guilabel:`template` within Weblate, though the naming might vary in
+your application.
+
+.. _gettext:
+
 GNU Gettext
 -----------
 
@@ -28,12 +43,16 @@ in their source code and the string needs to be translated to all languages,
 including English. Weblate does support this, though you have to choose explicitely
 this file format when importing resources into Weblate.
 
+.. _xliff:
+
 XLIFF
 -----
 
 XML based format created to standardize translation files, but in the end it
 is one of many standards in this area.
 
+XLIFF is usually used as bilingual.
+
 .. seealso:: https://en.wikipedia.org/wiki/XLIFF
 
 Java properties
@@ -41,6 +60,8 @@ Java properties
 
 Native Java format for translations.
 
+Java properties are usually used as bilingual.
+
 .. seealso:: https://en.wikipedia.org/wiki/.properties
 
 Qt Linguist .ts
@@ -48,13 +69,20 @@ Qt Linguist .ts
 
 Translation format used in Qt based applications.
 
+Qt Linguist files are used as both bilingual and monolingual.
+
 .. seealso:: http://qt-project.org/doc/qt-4.8/linguist-manual.html
 
+.. _aresource:
+
 Android string resources
 ------------------------
 
 Android specific file format for translating applications.
 
+Android string resources are monolingual, the :guilabel:`template` file being
+stored in different location than others :file:`res/values/strings.xml`.
+
 .. seealso:: https://developer.android.com/guide/topics/resources/string-resource.html
 
 .. note::
@@ -62,12 +90,16 @@ Android specific file format for translating applications.
     This format is not yet supported by Translate-toolkit (merge request is
     pending), but Weblate includes own support for it.
 
+.. _apple:
+
 Apple OS X strings
 ------------------
 
 Apple specific file format for translating applications, used for both OS X
 and iPhone/iPad application translations.
 
+Apple OS X strings are usually used as bilingual.
+
 .. seealso:: https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPInternational/Articles/StringsFiles.html
 
 .. note::