> I thought the same thing for English and French, no? When I learn English and French in school, we join letters.

No, English and French don't have a concept of "different characters for different places." The "c" in "cat", "act" and "topic" are all written exactly the same. It's not "cat", "a#t" and "topi*"

There are many languages, besides Arabic, that have a concept of distinct initial, medial and final characters. For example, the dozens of writing systems derived from Sanskrit.