Applying the analogy of other nouns to this form is mistaken, for the distinction between them is established both by reason and by attested usage.

As for transmitted evidence and attested usage, these are as we have explained. As for reasoning and analogy, several accomplished grammarians have recognized the distinction. Ibn al-Anbārī and others report that al-Farrā’ said: “The dual alif in hādhāni (‘these two’) is the alif of hādhā (‘this’). The nūn distinguishes the singular from the dual, just as the nūn in alladhīna (‘those who’) distinguishes the singular from the plural.”

Al-Mahdawī and others also report this from al-Farrā’. Al-Mahdawī’s wording is: “He stated that the alif is not the dual marker; rather, it is the alif of hādhā: ‘I added a nūn to it without changing it, just as I added one to the yā’ of alladhī (‘who’), saying alladhīna in every grammatical case.’” He continued: “Some Kufan grammarians said: ‘The alif here resembles that in yafʿalāni (‘they two do’), so it remains unchanged, just as that alif remains unchanged.’”

He said: “Al-Jurjānī said: ‘Since it is a noun consisting of two letters, one of which is a long-vowel letter, comparable to a short vowel, and since one of the two alifs must be omitted in forming the dual, it would be inappropriate to omit the first, lest the noun be reduced to a single letter. The dual marker was therefore omitted, while the nūn indicated the dual. There was no reason for the nūn to alter the original alif, so it remained unchanged in every grammatical case, just as it does in the singular.’”

Al-Mahdawī said: “Ismāʿīl the judge asked Ibn Kaysān about this question. He replied: ‘Since no case inflection appears in these pronouns, either in the singular or in the plural, the dual follows the same pattern as the singular, since the dual ought not to vary.’ Ismāʿīl said: ‘How excellent your explanation would be, had someone advanced it before you, providing reassuring precedent!’ Ibn Kaysān replied to him: ‘Then let the judge say it