Afrikaans Welkom
Albanian Mirë se vjen
Arabic (ahlan wasahlan) أهلا و سهلا
Aromanian Ghini vinit!
Azerbaijani Xoş gəlmişsiniz!
Basque Ongi etorri
Belarusian Прывiтанне (Pryvitańne)
Bosnian Dobrodošli
Breton Degemer mat
Bulgarian Добре дошли (dobre došli)
Catalan Benvinguts
Cebuano Maayong pag-abot
Chechen Märsha dooghiil
Chinese (Cantonese) 歡迎 (fòonying)
Chinese (Hakka) 歡迎 (fon ngiang)
Chinese (Mandarin) 歡迎光臨 [欢迎光临] (huānyíng guānglín)
Chinese (Taiwanese) 歡迎光臨 (huan-ging5-kong-lim5)
Cornish Dynnargh dhis
Corsican Bonavinuta
Croatian Dobrodošli
Czech Vítáme vás
Danish Velkommen
Dutch Welkom
Esperanto Bonvenon
Estonian Tere tulemast
Finnish Tervetuloa
French Bienvenue
Gaelic (Irish) Fáilte, Tá fáilte romhat Cead míle fáilte
Gaelic (Manx) Failt, Failt royd
Gaelic (Scottish) Fàilte, Ceud mìle fàilte
German Willkommen
Georgian შენი მობრძანება (šeni mobrżaneba)
Greek Καλώς ορίσατε (kalōs orisate)
Greenlandic Tikilluarit
Guaraní Eguahé porá
Hebrew (brukhim haba'im) ברוכים הבאים
Hindi स्वागत है (Svāgat hai)
Hungarian Üdvözlet
Icelandic Velkomin(n)
Igbo nno̱
Indonesian Selamat datang
Inuktitut ᐊᕆᐅᙵᐃᐹ (arionngaipaa)
Italian Benvenuti
Japanese ようこそ (yōkoso)
Javanese Sugeng rawuh
Jèrriais Séyiz les beinv'nu(e)(s)!
Khmer (sourm-sva-kum)
Korean 환영합니다 (hwangyong-hamnida)
Latvian Esiet sveicināti
Limburgish Wilkóm
Lithuanian Sveiki atvykę
Lojban fi'i
Malay Selamat datang
Maltese Merħba
Maori Haere mai
Marathi स्वागत आहे (Svāgat āhe)
Mikmaq Weltasualuleg
Mongolian Тавтай морилогтун (tavtai morilogtun)
Occitan Benvenguts
Persian (khosh amadid) خوش آمدید
Polish Witamy
Portuguese Bem-vindos
Punjabi ਜੀ ਆਇਆ ਨੂੰ (jī āiā nūng)
Romanian Bun venit Bine ai venit
Russian Добро пожаловать (Dobro požalovat')
Sardinian Bene bennios
Serbian Добро дошли (dobro doshli)
Sicilian Binvinutu
Slovak Vitajte
Slovenian Dobrodošli
Somali Soo dhowow
Spanish Bienvenido
Swahili Salamu
Swedish Välkomna
Tagalog Maligayang pagdating / Mabuhay
Tahitian Maeva / Manava
Thai ยินดีต้อนรับ (yindii ton rap)
Tigrinya እንቋዕ ብደሐን መጻእካ (ənqwaˋ bdeHen meSaəka)
Turkish Hoş geldiniz
Ukrainian Ласкаво просимо (Laskavo prosimo)
Urdu (khush amādīd) خوش آمديد
Uzbek Xush kelibsiz
Vietnamese Được tiếp đi ân cần
Volapük Vekömö
Walloon Benvnuwe
Welsh Croeso Croeso cynnes iawn
Zulu Uwamkelekile

Main source: http://www.omniglot.com/language/phrases/welcome.htm