Languages using right-to-left scripts

What is a script?

The Unicode Consortium's glossary uses the following definition:

Script: a collection of symbols used to represent text in one or more writing systems.

Microsoft offers the following definition on their globalization web site:

Script: A collection of characters for displaying written text, all of which have a common characteristic that justifies their consideration as a distinct set. One script can be used for several different languages (for example, Latin script, which covers all of Western Europe). Some written languages require multiple scripts (for example, Japanese, which requires at least three scripts: the hiragana and katakana syllabaries and the kanji ideographs imported from China). This sense of the word "script" has nothing to do with programming scripts such as Perl or Visual Basic Scripting Edition (VBScript).

Which languages are written right-to-left (RTL)?

Languages don't have a direction. Scripts have a writing direction, and so languages written in a particular script, will be written with the direction of that script.

Languages can be written in more than one script. For example, Azeri can be written in any of the Latin, Cyrillic, or Arabic scripts. When written in Latin or Cyrillic scripts, Azeri is written left-to-right (LTR). When written in the Arabic script, it is written right-to-left.

What languages use RTL scripts?

The following table gives a rough idea of modern spoken languages that can be written using RTL scripts, and where they are spoken. This data is gathered from information in the SIL Ethnologue. The Script Usage column shows all scripts that can be used for that language: the relative order gives a rough idea of frequency of use, and where the script usage is minor it appears in parentheses. The Potential Users column lists the number of overall speakers of that language (native and second language users). Some of the smaller languages are not mentioned, and the figures don't take into account users of liturgical languages.

The total number of potential users is of course an overestimate, because it doesn't take into account literacy levels or competing scripts or usage trends. Nonetheless, at 2,305,048,719 it indicates that the actual number of potential users possibly runs past a billion. The table lists 12 scripts, and 215 languages. Arabic accounts for a large proportion, with 189 languages and just over 2 billion potential users. No distinction is made between the various styles of Arabic, such as Nastaliq, Magribi, Kano, etc, or those that are abjads and those that are alphabetic. Nor, as mentioned, does it take into account the number of people using Arabic because of their religion.

The table doesn't include historical usage of scripts. For example, the Arabic script was formerly used throughout the Ottoman Empire and in many Central Asian regions. Other RTL scripts are not listed in the table because they are no longer used for modern communication, although academics and students around the world do need to be able to work with them. These include scripts such as Avestan, Minoan, Hatran, Imperial Aramaic, Kharoshthi, Lydian, Manichaean, Nabataean, Pahlavi, Palmyrene, Parthian, and Pheonician.

Which script should I use?

If a language can be written in more than one script, which script should a web designer or localizer use, or should the text be provided in all scripts?

The answer will depend on your target audience. The script may change for different countries or regions. The script may also change by legislation or with changes in government policy. For example, to reach the Azeri-speaking population in Iran, you would use Arabic script. From the late 1930s, Cyrillic was the script of choice in Azerbaijan itself and became policy in 1940. Due to the fall of the Soviet Union, beginning in 1991 a gradual switch to Latin occured, becoming mandatory for official uses in 2001. However, for your target audience and unofficial uses, you might want to use Cyrillic for older audiences and Latin for younger audiences, and most likely both to reach the general Azerbaijani population. If you want to reach all Azeri speakers, you would use all 3 scripts. (Note that there might be terminology and other differences among Azeri speakers in different countries, just as there are differences between English or French speakers in different countries.)

You also should be aware that your choice of script may have political, religious, demographic or cultural overtones. In countries where the language of higher learning was Russian, Cyrillic will be used by educated people. Latin is associated with Pan-Turkic movements, and more generally can indicate Western-tending movements. Arabic script has associations with Islamist movements.

More generally, just as you research which languages are required to serve different cultures, you may need to investigate the correct script or scripts to use. There are suggestions in the table above.