We agree that translation is a crucial part of the website-localization process. SP Booking like any other Joomla! component use language files. It includes .ini files which contains all of the English terms we have used. All you have to do is to translate listed below file(s):

• language\en-GB\en-GB.com_spbooking.ini
  (this file include words used in front-end - component view only)
  AND
• administrator\language\en-GB\en-GB.com_spbooking.ini
• administrator\language\en-GB\en-GB.com_spbooking.sys.ini
  (those files include words used in component back-end/admin only)
  AND Modules
• language\en-GB\en-GB.mod_spbooking_accomodation.ini
• language\en-GB\en-GB.mod_spbooking_destination.ini
• language\en-GB\en-GB.mod_spbooking_packages.ini
• language\en-GB\en-GB.mod_spbooking_search.ini
• language\en-GB\en-GB.mod_spbooking_transports.ini

Translate the strings to your language and save them as with native language prefix name and copy to your language folder. File (.ini) must be saved as UTF-8 without BOM encoding. You don’t have to translate all strings from all files, select & translate only those which you really need. Each translated string must be enclosed by double quotes, always.

Before translation change the filenames, for example:
from: en-GB.com_spbooking.ini
to: xx-XX.com_spbooking.ini

Where xx-XX is a LANG-PREFIX, for example, es-ES – for Spanish (Español). Once the phrases inside file have been translated and file renamed, you can copy your language file into your "native" language directory using an FTP client.