The BrowserCRM language files are in the directory

/lang

You will see a number of subdirectories

/lang
  /en
  /fr
  /de
  /es

English it the master language. To make a new translation, copy the directory /lang/en to a new directory with your 2-letter language code, e.g. /lang/xx

Inside the new /lang/xx folder are the individual language files for each module.

_Global.inc
Admin.inc
Company.inc
etc

You need to edit each file using a text editor. The contents of the file is a series of statements in the format var = term. Please edit the part on the right-hand side.

$L['LanguageName'] = 'English';

$L['CalendarPopup'] = 'Calendar'; //used for Popup Mini Calendar html title tag
$L['ImageIsNew'] = 'New'; //use in title (alt) tag for New image
$L['ImageIsUnseen'] = 'Unseen'; //use in title (alt) tag for New image

So for French:

$L['LanguageName'] = 'Français';

$L['CalendarPopup'] = 'Calendrier'; //used for Popup Mini Calendar html title tag
$L['ImageIsNew'] = 'Nouveau'; //use in title (alt) tag for New image
$L['ImageIsUnseen'] = 'Pas encore vu'; //use in title (alt) tag for New image

You must save the files using the character set UTF-8.