The big translators like Google, Bing(Microsoft), Baidu and Yandex provide translation services for world major 101 languages like English, French, Spanish, German, Hindi, Arabic, Chinese, Japanese and so on.
And each translaor provides its specific translators for rare languages. Google, Bing, Baidu and Yandex provide translators for 32, 30, 99 and 21 rare languages respectively.

Major languages common to most of translators:

Afrikaans, Albanian, Amharic, Arabic, Armenian, Assamese, Azerbaijani, Basque, Bengali, Bhojpuri, Bosnian, Bulgarian, Catalan, Chichewa, Chinese, Creole, Croatian, Czech, Danish, Dhivehi, Dutch, English, Estonian, Filipino, Finnish, French, Galician, Georgian, German, Greek, Gujarati, Hausa, Hebrew, Hindi, Hmong, Hungarian, Icelandic, Igbo, Indonesian, Irish, Italian, Japanese, Kannada, Khmer, Kinyarwanda, Konkani, Korean, Kurdish, Kyrgyz, Lao, Latvian, Lingala, Lithuanian, Luganda, Macedonian, Maithili, Malagasy, Malay, Malayalam, Maltese, Maori, Marathi, Myanmar, Nepali, Norwegian, Odia, Pashto, Persian, Polish, Portuguese, Punjabi, Romanian, Russian, Samoan, Sepedi, Serbian, Sesotho, Shona, Sindhi, Sinhala, Slovak, Slovenian, Somali, Spanish, Swahili, Swedish, Taiwanese, Tamil, Tatar, Telugu, Thai, Tigrinya, Turkish, Turkmen, Ukrainian, Urdu, Vietnamese, Welsh, Xhosa, Yoruba, and Zulu

Rare languages specific to Google:

Aymara, Bambara, Belarusian, Cebuano, Corsican, Dogri, Esperanto, Ewe, Frisian, Guarani, Hawaiian, Ilocano, Javanese, Kazakh, Krio, Kurdish Central, Latin, Luxembourgish, Meiteilon, Mizo, Mongolian, Oromo, Quechua, Sanskrit, Scots Gaelic, Sundanese, Tajik, Tsonga, Twi, Uyghur, Uzbek, and Yiddish

Rare languages specific to Bing:

Bashkir, Bodo, Cantonese, Chinese Classic, Dari, Dogri, Faroese, Fijian, French Canada, Inuinnaqtun, Inuktitut, Inuktitut Latin, Kashmiri, Kazakh, Klingon, Kurdish Central, Mongolian, Mongolian Traditional, Portuguese Portugal, Queretaro Otomi, Serbian Latin, Setswana, Sorbian Lower, Sorbian Upper, Tahitian, Tibetan, Tongan, Uyghur, Uzbek, and Yucatec Maya

Rare languages specific to Baidu:

Acehnese, Akan, Arabic Algerian, Arabic Tunisian, Aragonese, Asturian, Aymara, Balochi, Bashkir, Belarusian, Bemba, Berber, Blin, Bislama, Breton, Cantonese, Cebuano, Cherokee, Chinese Classic, Chuvash, Cornish, Corsican, Crimean, English Old, Esperanto, Faroese, French Canada, French Middle, Frisian, Friulian, Fula, Greek Ancient, Guarani, Hakha Chin, Hawaiian, Hiligaynon, Hupa, Ido, Ingush, Interlingua, Inuktitut, Javanese, Kabyle, Kalaallisut, Kanuri, Kapampangan, Kashmiri, Kashubian, Kikongo, Klingon, Latgalian, Latin, Limburgish, Lojban, Low German, Luxembourgish, Manx, Marshallese, Montenegrin, Morisien, Muscogee, Ndebele Southern, Neapolitan, NKo, Norwegian Bokmal, Norwegian Nynorsk, Occitan, Ojibwe, Oromo, Ossetian, Papiamento, Portuguese Portugal, Quechua, Romani, Romansh, Rusyn, Sami Northern, Sanskrit, Sardinian, Scots Gaelic, Serbian Latin, Serbo Croatian, Shan, Silesian, Songhay, Sorbian Lower, Sorbian Upper, Sundanese, Syriac, Tagalog, Tajik, Tetum, Tsonga, Twi, Venda, Walloon, Wolof, Yiddish, and Zaza

Rare languages specific to Yandex:

Bashkir, Belarusian, Cebuano, Chuvash, Esperanto, Hill Mari, Javanese, Kazakh, Latin, Luxembourgish, Mari, Mongolian, Papiamento, Scots Gaelic, Sindarin, Sundanese, Tajik, Udmurt, Uzbek, Yakut, and Yiddish