To translate hoteldruid to another language duplicate the directory
/includes/lang/en renaming it to the acronym of the new language
(maximum 3 letters). After that change the full name of the language in
the file l_n inside that directory.

Now you should be able to choose the new language when installing or
from "Configure and customize", but naturally it will still display
messages in English. To change them you must edit all files in the new
language directory changing the phrases in english between quotation
marks (right column) with their translations. Remember that you must
always use \" instead of " and \$ instead of $. See comments in the
files (lines that begin with #) for special cases. As you change
phrases in the files you can see how they change also in the
corresponding pages in the browser.

The files are encoded with unicode utf-8, so you shold use a text
editor that supports this encoding. For example in Linux you can use
Kate that supports saving in utf-8 even if that's not set as your
default locale.

Please check if a translation for your language already exists on the
hoteldruid website, in this case you can download it and eventually
edit it to translate only the phrases that are still in English (you
will find them at the end of each file).

If you make a translation in your own language feel free to send it to
me at under the GPLv3 license, so I can put it
on hoteldruid website for download.