Today Afghanistan, Iran, India, Pakistan and China are the main non-Arabic speaking states using the Arabic alphabet to write one or more official national languages, including Baluchi, Brahui, Persian, Pashto, Central Kurdish, Urdu, Sindhi, Kashmiri, Punjabi and Uyghur. An Arabic alphabet is currently used for the following languages: Baluchi, Brahui, Persian, Pashto, Central Kurdish, Urdu, Sindhi, Kashmiri, Punjabi and Uyghur. Garshuni,Kazakh,Kurdish,Uzbek,Somali,Pashto,Dari,Kashmiri,Saraiki.
A number of countries use the Arabic alphabet to write their own languages, and usually use an alphabet derived from Arabic by adding Arabic characters that are not used by the Arabs themselves to include all the exits and pronunciations of the languages.
Speakers in previously unedited languages used the Arabic alphabet as a written basis for their mother tongue. In addition, because most of the education was religious at one time, non-Arab Muslims were writing in the Arabic alphabet any language they spoke Out. This led to the Arabic writing becoming the most used writing during the Middle Ages. The most prominent languages that still use the Arabic alphabet in the present time are Persian (Farsi: Farsi or Zaban Farsi) spread throughout Iran and some parts of Central Asia; Kurdish (Urdu: Urdu) in Pakistan and India, and many other languages
I am unsure of how many currently, or formerly, used the Arabic alphabet, but Swahili was originally written in the Arabic alphabet until it was Romanized by the colonial powers.
I believe, you have included the Jawi? A writing system of some languages of the Southeast Asian countries. Anyway, of the exact number, I have no idea.
Several Slavic languages have occasionally been written in Arabic script; on the page http://kcmamu.livejournal.com/21876.html four of them can be seen (Belorussian, Bulgarian, Polish and Serbo-Croat, from top to bottom).
Bahasa Malaysia 'Malaysian Language' uses the distinct scripts: the Jawi and the Rumi. Jawi is the Arabic form of writing while Rumi is, of course, the Roman alphabet. Since the Rumi script is considered the easier of the two and also the official script, it is is the current script of Malaysian language. Jawi writing was very common in Malaysia in the past. However, I am unsure for how long it has been used, and when they stopped writing in Jawi, but older people in Malaysia usually can write in Jawi script (Arabic script).