Smart PHP Calendar has flexible i18n engine.
Default calendar and interface language is English but you can use the built-in languages or translate the whole application to your language easily.
// Example German Translation
// system/i18n/de.php
<?php
$spcI18n = array(
//month names
'January' => 'Januar',
'February' => 'Februar',
'March' => 'März',
...
...
...
Now you can choose your language from the "Calendar Settings" and use Smart PHP Calendar in your own language.