Bhaktamar Stotra is traditionally regarded as a Sanskrit hymn composed by Acharya Manatunga in the 7th century CE. It is widely accepted that the original text is in Sanskrit, not Prakrit. The Digambaras count 48 verses, while the Śvetāmbaras traditionally count 44 verses. These differences are about recension and tradition, not about a different core content. ( en.wikipedia.org)

Why Sanskrit and not Prakrit?

• Language of authorship: Mantunga (Manatunga) is described in Jain tradition as composing in Sanskrit. This choice reflects his training in the Sanskrit literary and scholarly milieu of his time, a common practice for high-status devotional and doctrinal works in that era. ( en.wikipedia.org)
• Purpose and style: Sanskrit was the liturgical, pan-Indic language used for poetry, philosophy, and ritual in many Jain and broader Indian scholarly circles. Writing Bhaktamar in Sanskrit aligned with its refined, highly stylized metrical composition (vasantatilaka meter) and its devotional, pan-religious appeal. ( en.wikipedia.org)
• Prakrit usage in Jain literature: Prakrit has been used for many Jain texts, especially in more vernacular or regional contexts, but Bhaktamar stands out as a Sanskrit composition from its traditional attribution. The choice is not framed as a strategy to attract Sanskrit-speaking masses so much as a reflection of the author’s linguistic milieu and the text’s aims as a prestige devotional hymn. ( en.wikipedia.org)

Notes on tradition

• Digambara vs. Śvetāmbara: The main difference here is the number of verses (48 vs 44) and some textual elements, not the language. The Sanskrit origin is commonly accepted across traditions, with the textual tradition diverging in later recensions. ( en.wikipedia.org)

If you’d like, I can point you to Jain sources that discuss Mantunga and Bhaktamar in more detail, and how the verse counts differ between Digambara and Śvetāmbara traditions.