What are the letters of al-lissan?

Al-Lissan, or "Al-Lisan," refers to the Arabic Word for "the tongue." In the context of the Arabic language, it may also pertain to a specific work or study of Arabic linguistics. The Arabic alphabet consists of 28 letters, and while there isn't a specific set of letters called "al-lissan," the term emphasizes the importance of language and expression in Arabic culture. If you meant something specific by "al-lissan," please provide more context.