Привет на всех языках, почти...

Afrikaans: hallo
Albanian: tungjatjeta
Arabic: مرحبًا (marħában)
Armenian: բարև (barev), ողջույն (oghǰuyn)
Asturian: hola
Basque: kaixo
Bengali: নমস্কার (nomoskar)
Bosnian: zdravo, ćao, merhaba, selam
Bulgarian: здравей (zdrávej, familiar), здравейте (zdrávejte, formal)
Catalan: hola
Chinese: 你好 (nǐ hǎo), 您好 (formal nín hǎo)
Croatian: zdravo, ćao, bok, bog
Czech: ahoj, nazdar (informal), dobrý den (formal)
Danish: hej, dav, god dag (formal)
Dutch: hallo, hoi, goedendag
English: hello
Esperanto: saluton
Estonian: tere
Faroese: hey, halló
Fijian: bula
Finnish: terve, moi, hei, moikka
French: salut (informal), bonjour
Galician: ola
Georgian: გამარჯობა (gamardžoba)
German: hallo, guten Tag
Gilbertese: mauri
Greek: γειά, γειά σου (yeiá sou), γειά σας (yeiá sas, formal)
Hausa: sannu
Hawaiian: aloha
Hebrew: שָׁלוֹם (shalóm)
Hindi: नमस्ते (namasté)
Hmong: nyob zoo
Hungarian: szia, sziasztok pl.(informal); szervusz, szervusztok pl. (formal)
Icelandic: halló, hæ
Indonesian: hai
Irish: dia is muire dhuit
Italian: ciao, salve, buongiorno
Japanese: おはようございます (ohayō gozaimásu = good morning, polite), こんにちは (kónnichi wa = good day), こんばんは (kómban wa = good evening), おはよう (ohayō = hello, informal)
Kazakh: сәлем (səlem), салам (salam), сәлеметсіздер (səlemetsizder, formal)
Korean: 안녕하세요 (annyeonghaseyo, formal), 안녕 (annyeong, informal)
Lao: (sabai dii)
Latin: salve, ave
Lithuanian: labas, sveikas (informal), sveiki (formal)
Norwegian: hallo, hei, god dag (formal), halla (informal)
Persian: سلام (salâm); religious: سلام علیکم (salamon alaikum); literary: درود (dorood); morning: صبح بخیر (sobh bekhair), afternoon: ظهر بخیر (zohr bekhair), evening: عصر بخیر (asr bekhair)
Polish: cześć (informal), witaj, witajcie, witam (more formal), dzień dobry (formal)
Portuguese: oi, olá, bom dia
Romanian: salut, bună, noroc (informal), bună ziua (formal)
Russian: привет (privét, informal), здравствуйте (zdrávstvujte, formal), добрый день (dóbryj den’)
Sanskrit: नमस्कार (namaskāram)
Cyrillic: здраво, ћао
Roman: zdravo, ćao
Dumela (singular object; e.g. "Dumela, rra" = "Hello sir")
Dumelan (plural object; e.g. "Dumelang, borra" = "Hello gentlemen")
Sicilian: ciao, salutamu
Slovak: ahoj, servus, nazdar (informal), dobrý deň (formal)
Slovene: pozdravljen, zdravo, dober dan
Spanish: hola, buenos días
Swahili: jambo
Swedish: hallå, hej, god dag (formal)
Swiss German: sälü, hoi, hallo
Tamil: வணக்கம் (vanakkam)
Thai: สวัสดีครับ (sàwàtdee kráp) m., สวัสดีค่ะ (sàwàtdee kâ) f.
Turkish: merhaba
Tuvan: экии (ekii)
Ukrainian: привіт (pryvít, informal), добрий день (dobry den, formal)
Vietnamese: chào (ông, bà, cô, anh, chị, em, quí vị — depending on gender and relative social status of person addressed)
Welsh: helo
Zulu: sawubona