This line is wrong:
.isEmpty("Language")
A field key in Wix collections never starts with a capital letter, so maybe you used the field label instead or just misspelled the field key, but you should fix it.
This line is wrong:
.isEmpty("Language")
A field key in Wix collections never starts with a capital letter, so maybe you used the field label instead or just misspelled the field key, but you should fix it.