|Reading & Writing|
Nasta'liq or Nasta'leegh (نستعلیق) is a specific style for writing in the Arabic alphabet. It is the preferred style for writing Urdu, but is mostly considered a form of calligraphic art for writing other languages, specially Persian and Ottoman Turkish. The name derives from mixing Naskh and Ta'leeq, two other writing styles, of which Nasta'liq is a descendant.
In Iran, Nasta'liq is usually written with a somewhat thick reed pen (with a tip of about 5mm), and a special kind of carbon ink. In Pakistan, various kinds of pens and inks are used, because of the higher usage of the style.
Producing high quality Nasta'liq in print is a demanding process. For example, Monotype's attempt to implement Nasta'liq for photo composer typesetting resulted in a glyph repertoire of 20,000 different glyphs. See explanation below:
This is due to the vertical displacement of characters when they are joined together. As more characters join together (usually 2-5), each one of the previous ones moves slightly up. The OTF font specification can handle this and beautiful nasta'liq is now possible on regular rendering engines such as the Windows Uniscribe engine that ships with Microsoft Windows 2000 onwards.
As Urdu fontography is evolving, a number of issues with its Unicode representation have been raised. At the moment, the font that complies best with Unicode and OTF is Nafees Nasta'liq, produced by CRULP (Center for Research in Urdu Language Processing) 
If you have Nafees Nasta'liq installed, the text and image below should be identical. Note the previous letters being shifted up: