To hide Language on One Page, you can follow these.
#1. First, find Page ID.
In my example, it is: #collection-67bd2c781e1a2c30e9e2622c
#2 . Next, use this code to Custom CSS box
#collection-67bd2c781e1a2c30e9e2622c
div.language-picker
{
display: none !important;
}
