it's all Greek to me

First quoted as it was Greek to me in Julius Caesar by Shakespeare, possibly translated from a sentence in Medieval Latin.

• "I tried reading the instructions, but it’s all Greek to me."
• "But thoſe that vnderſtood him, ſmil'd at one another, and ſhooke their heads: but for mine owne part, it was Greeke to me."
• "During the processions they trilled and quavered most melodiously betwixt their teeth I do not know what antiphones, or chantings, by turns. For my part, ’twas all Hebrew-Greek to me, the devil a word I could pick out on’t;"
• ""Well," said Alfred, "it may be a letter, but I confess it is all Greek to me. I certainly do not see why you wish to keep it a secret. Tell me.""
• "I ran after him, and received an order to go aloft and “slush down the main-top mast.” This was all Greek to me, and after receiving the order, I stood staring about me, wondering what it was that was to be done."
• "“Look here, Mr. Count,” he said; “I am only a rough Englishman, and a lot of what you have been saying about mission and that sort of thing is just so much Greek to me.”"
• "“It's more like some firm's paper. All this printed stuff at the top. Drachenflieger. Drachenballons. Ballonstoffe. Kugelballons. Greek to me.”"
• "A Parsi lawyer was examining a witness and asking him question regarding credit and debit entries in account books. It was all Greek to me."
• "Cavanaugh explained the network-affiliate relationship, which of course was all Greek to me and remained so even after his explanation."
• "[…]it was expected of me, or it was considered an honor, to lecture on seventeenth-century philosophy: Descartes (which was all Greek to me), Descartes to Spinoza."

• it's all Chinese to me
• (I can’t) make head or tail of
• double Dutch