Right-to-left
In a right-to-left, top-to-bottom script (commonly shortened to 
right to left or abbreviated RTL), writing starts from the right of the page and continues to the left. Examples of right-to-left scripts are:
- Arabic script - used for Arabic, Persian, Urdu and many other languages.
- Hebrew alphabet - used for Hebrew, Yiddish and some other Jewish languages.
- Syriac alphabet - used for varieties of the Syriac language.
- Thaana - used for Dhivehi.
- N'Ko script - used for several languages of West Africa.
- Samaritan alphabet - closely related to Hebrew, used for the Samaritans' writings
- Mandaic alphabet - closely related to Syriac, used for the Mandaic language
- Imperial Aramaic alphabet - ancient, closely related to Hebrew and Phoenician
- Phoenician alphabet - ancient, closely related to Hebrew and Imperial Aramaic
- Lydian alphabet - ancient; some texts are left-to-right or boustrophedon
- Cypriot syllabary
- Kharosthi - an ancient script of India
- Old South Arabian
- Avestan alphabet
- Pahlavi scripts
- Old Turkic alphabet
- Etruscan language - extinct language
- Umbrian language - an extinct Italic language formerly spoken by the Umbri in the ancient Italian region of Umbria.
Right-to-left can also refer to 
top-to-bottom, right-to-left scripts such as Chinese, Japanese, and Korean, though they are also commonly written 
left to right.
Right-to-left, top-to-bottom text is supported in common consumer software.[1] Often this support must be explicitly enabled. For mixing right-to-left text with left-to-right text, see bi-directional text.
On the other hand, at present, handling of downward text is incomplete. For example, HTML has no support for it and tables are necessary to simulate it. However, CSS level 3 includes a property "writing-mode" which can render tategaki when given the value "tb-rl". Word processors and DTP software have more complete support for it.
RTL Wikipedia languages
RTL Wikipedias according to bugzilla.wikimedia.org [2] are listed in below:
- 'ar' => 'العربية', Arabic
- 'arc' => 'ܐܪܡܝܐ', Aramaic
- 'arz' => 'مصرى', Egyptian Spoken Arabic
- 'bcc' => 'بلوچی مکرانی', Southern Balochi
- 'bqi' => 'بختياري', Bakthiari
- 'ckb' => 'Soranî / کوردی', Sorani
- 'dv' => 'ދިވެހިބަސް', Dhivehi
- 'fa' => 'فارسی', Persian
- 'glk' => 'گیلکی', Gilaki
- 'he' => 'עברית', Hebrew
- 'ku' => 'Kurdî / كوردی', Kurdish
- 'mzn' => 'مازِرونی', Mazanderani
- 'pnb' => 'پنجابی', Western Punjabi
- 'ps' => 'پښتو', Pashto,
- 'sd' => 'سنڌي', Sindhi
- 'ug' => 'Uyghurche / ئۇيغۇرچە', Uyghur
- 'ur' => 'اردو', Urdu
- 'yi' => 'ייִדיש', Yiddish