 In several works al-Fārābī analyses features of Arabic as a language. Some of these works contain comparisons between Arabic and other languages: Greek, Syriac, Persian, and Sogdian in [Letters], Greek and Persian in [Commentary on De Interpretatione], and Greek in [Expressions]. Al-Fārābī’s comments on Greek include several mistranslations and dubious grammatical remarks, making it clear that he didn’t read Greek (for al-Fārābī’s knowledge of languages see Zimmermann 1981: xlviif). Also al-Fārābī has a strong tendency to classify languages as (1) Arabic and (2) “other languages”. So these comparisons are far from being a serious contribution to comparative linguistics, and one asks why he includes them. 