diff --git a/phpgwapi/doc/lang_files.txt b/phpgwapi/doc/lang_files.txt
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+For language translation, please read these rules:
+
+
+Format of a lang file:
+
+{phrase}{TAB}{appname}{TAB}{LANG_CODE}{TAB}{translation}
+
+e.g:
+
+first name	common	en	First Name
+first name	common	de	Vorname
+
+
+Filenames:
+phpgw_{LANG_CODE}.lang
+
+e.g.
+English	phpgw_en.lang
+German	phpgw_de.lang
+
+Please look at the content of the 'languages' table for the correct
+setting of the {LANG_CODE}.
+
+
+Rules:
+
+1.  The appname 'common' is reserved for the API and for application names in
+  each application.  Phrases that are common are loaded for all apps and for
+  the homepage/navbar.  Please DO NOT place more than a few phrases in 'common'.
+  These should be only enough for the appname to display correctly in the navbar
+  for the most part.  Please set the appname field to your application name.
+
+2.  Consult an API developer prior to adding or editing files in the
+  phpgwapi/setup language files, and prior to adding a lot of phrases
+  to 'common' within an application/setup dir.
+
+3.  TRANSLATION to other languages MUST be based upon the english language
+  files (phpgw_en.lang in each app/setup directory).  Since most of the
+  developers are using English as their primary language, those should
+  have the most complete list.
+
+4.  Language files for other than English should NOT have additional
+  phrases.  If some phrase needs to be added to the English file, please
+  consult the API or application developer to let them know before you
+  add missing phrases.
+
+5. Please be careful not to conflict with or duplicate an API lang entry.
+  Conflicts should be checked for by using setup to load the language you are
+  working with.  Also, if more than a couple of apps are using the same or
+  similar lang entry, it should most likely be moved to the API lang files.
+  This is so that the size of the db is kept as small as possible.
+
+6.  Please do not have multiple copies of an entry for different apps when
+  it can be avoided.  e.g. the phrase 'add widget' set to 'preferences',
+  'admin', 'common' and the 'appname'.  When in doubt use common, so that
+  it will show in prefs/admin, etc.
+