Languages aren't all just simple alphabets like English. Some languages use ligatures to combine characters. In English, things like 'fi' and 'ffl' can be done almost automatically, and is optional, but other languages have stronger and more important rules.
As a simple example, in German the ligature ß is not a simple ligature for 'ss' but a combination of two previous ligatures; long s with round s ("ſs") and long s with (round) z "ſʒ"). Various spelling reforms have simplified the orthography, but "Maßen" and "Massen" are still different words.
Quoting from a Wikipedia page, "Urdu (one of the main languages of South Asia), which uses a calligraphic version of the Arabic-based Nasta`liq script, requires a great number of ligatures in digital typography. InPage, a widely used desktop publishing tool for Urdu, uses Nasta`liq fonts with over 20,000 ligatures"
Then there are rules for presentation. "Complex text layout ... refers to the typesetting of writing systems in which the shape or positioning of a grapheme depends on its relation to other graphemes." - http://en.wikipedia.org/wiki/Complex_text_layout . Cursive English is closest we have to complex text layout; while there are "cursive" fonts where each of the characters is in cursive the letters don't merge. Now imagine a language where smooth connections and fancy curlicues in the "right" places were essential for being seen as erudite, and where "right" depended on 5 years of learning.
As a simple example, in German the ligature ß is not a simple ligature for 'ss' but a combination of two previous ligatures; long s with round s ("ſs") and long s with (round) z "ſʒ"). Various spelling reforms have simplified the orthography, but "Maßen" and "Massen" are still different words.
Quoting from a Wikipedia page, "Urdu (one of the main languages of South Asia), which uses a calligraphic version of the Arabic-based Nasta`liq script, requires a great number of ligatures in digital typography. InPage, a widely used desktop publishing tool for Urdu, uses Nasta`liq fonts with over 20,000 ligatures"
Then there are rules for presentation. "Complex text layout ... refers to the typesetting of writing systems in which the shape or positioning of a grapheme depends on its relation to other graphemes." - http://en.wikipedia.org/wiki/Complex_text_layout . Cursive English is closest we have to complex text layout; while there are "cursive" fonts where each of the characters is in cursive the letters don't merge. Now imagine a language where smooth connections and fancy curlicues in the "right" places were essential for being seen as erudite, and where "right" depended on 5 years of learning.