Cé is used where the hypothetical is 'unreal' in the sense that it is the opposite of what the speaker is advising.
The translation is provided on the same page:
Not doing this may be/prove unwise.
Black Speech, Nandorin, Noldorin, Quendya, Quenya, Sindarin, Telerin are languages conceived by Tolkien and they do not belong to us; we neither can nor do claim affiliation
with Middle-earth Enterprises nor Tolkien Estate.