That's Greek to me or It's (all) Greek to me is an idiom/dead metaphor in English, claiming that an expression is incomprehensible, either due to complexity or imprecision. The expression may be used with respect to verbal expressions with excessive jargon of dialect, mathematics, or science. The metaphor makes reference to the Greek language and the Greek alphabet (either ancient or modern).
The usage of the metaphor in English language traces back to early modern times:
Ironically, this line worked literally. The speaker Casca has just returned from a celebration at which he says that Cicero spoke in Greek, and "it was Greek to me."
The expression is almost exclusively used with reference to the speaker (generally "Greek to me"; rarely or never "Greek to him").
It may have been a direct translation of a similar phrase in Latin: "Graecum est; non legitur" ("it is Greek, [therefore] it cannot be read"). This phrase was increasingly used by monk scribes in the Middle Ages, as knowledge of Greek was dwindling among those who were copying manuscripts in monastic libraries.
Different languages have similar formulations. Many have picked the point of reference to be a foreign language with another alphabet or writing system.
This is an example of the usage of demonyms in relation to the ability of a people to be understood, comparable to the development of the words barbarian (one who babbles), Nemecky (Slavic for "one who is not understood", indicating Germans).
| Language | Phrase | IPA | "target" language |
|---|---|---|---|
| English | It's Double Dutch. | Dutch | |
| English | That's Greek to me. | Greek | |
| Arabic | .يتحدث باللغة الصينية | Yataḥaddaṯ bil-luġah al-Ṣīnīyah | Chinese |
| Arabic | .يحكي كرشوني | Yaḥkī Karšūnī | Garshuni |
| Bulgarian | Все едно ми говориш на китайски. | Chinese | |
| Chavacano | Aleman ese comigo. | German | |
| Chinese Mandarin | 看起來像天書。 | Kàn qílái xiàng tiānshū | "Book from the Heaven" (Referring to an unknown writing system.) |
| Chinese Mandarin | 聽起來像鳥語。 | Tīng qílái xiàng niǎoyǔ | "Sounds/tongue of the Birds" (Unknown phonology system.) |
| Chinese Cantonese | 呢啲喺雞腸呀。 | "Chicken Intestines", referring to the Latin Alphabet | |
| Croatian | To su za mene španska sela. | Spanish | |
| Dutch | Dat is Chinees voor mij. | Chinese | |
| Esperanto | Tio estas Volapukaĵo. | Volapük | |
| Finnish | Täyttä hepreaa. | Hebrew | |
| French | c’est du chinois. | Chinese | |
| German | Das kommt mir spanisch vor. | Spanish | |
| Greek | Αὐτὰ μοῦ φαίνονται κινέζικα. | Chinese | |
| Hebrew | זה סינית בשבילי | Chinese | |
| Hungarian | Ez nekem kínai. | Chinese | |
| Italian | Questo per me è arabo/aramaico/ostrogoto | Arabic, Aramaic, Ostrogoth | |
| Japanese | ちんぷんかんぷん | chin pun kan pun | Chinese |
| Latin | Graecum est; non legitur | Greek | |
| Latvian | Tā man ir ķīniešu ābece | Chinese | |
| Lithuanian | Tai man kaip kinų kalba. | Chinese | |
| Low Saxon | Dat kümmt mi spaansch vör. | Spanish | |
| Persian | انگار ژاپنی حرف می زنه | Japanese | |
| Polish | To dla mnie chińszczyzna. | Chinese | |
| Portuguese | Isto é chinês/grego para mim. | Chinese/Greek | |
| Romanian | Esti turc? | Turkish | |
| Russian | Это для меня китайская грамота. | Chinese | |
| Serbian | То су за мене шпанска села. To su za mene španska sela. | Spanish | |
| Serbian | Ко да кинески причаш. Ko da kineski pričaš. | Chinese | |
| Sinhalese | Melo Huththak Therennae. | Sinhalese | |
| Slovak | To je pre mňa španielska dedina. | Spanish | |
| Slovene | To mi je španska vas | Spanish | |
| Spanish | Esto me suena a chino. | Chinese | |
| Swedish | Det är rena grekiskan. | Greek | |
| Turkish | Konuya Fransız kaldım. | French | |
| Ukrainian | Це для мене китайська грамота. | Chinese | |
| Yiddish | ס'איז תּרגום־לשון צו מיר | Aramaic |