The use of vocatives to introduce important sections of the Qur’ān is an established fact. Allāh communicates with the Prophet, ‘Banī I’srā’īl’ (the Children of Israel) and ‘those who believe’ (يٰأيّها الّذين أمنوا…) inter alia, through the medium of the text by way of various stylistic and grammatical devices such as vocative particles:
One proposed explanation for the Muqaṭṭa’āt, which would go some way to explaining their consistent placement at the outset of chapters, is that they are vocative formulas for attracting the attention of the Prophet or his audience. As-Suyūtī, in his I’tqān, mentions a number of alternative explanations for each formula, drawing the conclusion that each one refers in some way to the Prophet of Islam: for example, Ṭa-Ha is supposed to have meant ‘O man’ in one of the early Arabic dialects of the ‘Akk, and by analogy was used to attract the attention of Muḥammad. Yā-Sīn is also related as denoting ‘O man’ in the dialect of the Ṭayy, and according to Ibn ‘Abbās, was used as a term of esteem or affection to refer to the Prophet.
The thesis of the Muqaṭṭa’āt being vocatives is further supported by the fact that in every case, the text following them is couched in the second person singular, a rhetorical device that is not employed anywhere else in the Qur’ān:
By substituting the Muqaṭṭa’āt in each case with the Arabic يا محمّد, we notice that the meaning of the accompanying text is not altered in any way. It would not be fanciful to suggest that, whilst the Muqaṭṭa’āt themselves changed form depending on the concomitant message being relayed, the essential import of them as forms of address or vocative devices remained the same.
Special mention here must be made of Alan Jones’ assertion that the letters were battle cries used by the Prophet of Islām in order to arouse the attention of the Arabs. He draws on traditions related by ar-Rāzī, amongst others, that the Muqaṭṭa’āt Ḥa-Mīm were employed to communicate the message of the Qur’ān more effectively by way of rousing oaths in the vernacular known intimately by the Hijāzī Arabs.
Whilst this is a plausible explanation for the manifestation and incidence of the Muqaṭṭa’āt, it does not account for the various combinations or provide an answer as to their occurrence in some cases across multiple successive chapters.
 Dr Muhammad Muhsin Khan and Dr Muhammad Taqi-ud-Din Al-Hilali: see, for example, Sūrat al-Baqarah pp.14-76.
 Jalāl al-Dīn al-Suyūtī. 2000. al-Itqan fī ‘Ulūm al-Qur’ān (Vol. II). Dār Al Kutub Al ‘Ilmiya. pp.15-21.
 Dr Muhammad Muhsin Khan and Dr Muhammad Taqi-ud-Din Al-Hilali, op. cit., pp.77-78.
 Ibid., p.479.
 Jones, Alan Jones. 1962. ‘The Mystical Letters of the Qur’an’. Studia Islamica 16. pp. 5-11.