tu ne sais plus il est qui
This is an indirect interrogative construction and the word order is the same as in English
So why doesn't qui il elide to qu'il?
"Qui" is never elided and does not need to be because the sound "i" never conflicts with any other vowel sound.
Besides, if you elided "qui", you get "qu'" which is "que", which means "what".
Why not connais?
You can say:
"tu le connais", because you are acquainted/familiar with him as a person;
but "tu sais qui il est", because "qui il est" is a piece of information you have had learned.
Ah, got it! Thank you very much!
I wrote "Tu ne sais plus qui'l est" and I had it correct but it said I missed a space in "qui_il."
Why don't they mash into one word?
No, "qui" never elides (never changes to qu').
i dont understand the mean of this sentence.
"You don't know anymore" = you have forgotten
Is the justification for using il over ce in this sentence based on usage when talking about not knowing who a specific person is (il) vs figuratively not knowing who a person is or understanding why they are acting in a certain manner (ce)?
Both "qui c'est" and "qui il est" are used with sometimes a nuance.
"Je sais qui c'est" is about his/her identity (name, title, profession...)
"Je sais qui il est" is about his personality.
It's the subtle nuances that really make you understand a language. Always appreciate your insight. Much thanks!