Error with language

[mada0068]

I have installed version 1.9 and get stuck in some places, but I am solving them. Just for your information. Running in Ubuntu 22.04, php 8 and MySQL.

When getting the locale language from browser, my browser returns only Spanish, not Spanish-Es, so PHP throw an error. I hava harcoded the language (by now) in webcalendar.php, and will chase the error.