OET interlinear ACTs 26:24

uW Translation Notes:

Note 1 topic: translate-tense

ὁ Φῆστος & φησιν

¬the Festus & (Some words not found in SR-GNT: ταῦτα Δέ αὐτοῦ ἀπολογουμένου ὁ Φῆστος μεγάλῃ τῇ φωνῇ φησίν Μαίνῃ Παῦλε Τά πολλά σέ γράμματα εἰς μανίαν περιτρέπει)

To call attention to a development in the story, here Luke uses the present tense in past narration. If it would not be natural to do that in your language, you could use the past tense in your translation. Alternate translation: [Festus said]

Note 2 topic: figures-of-speech / personification

τὰ πολλά σε γράμματα εἰς μανίαν περιτρέπει

(Some words not found in SR-GNT: ταῦτα Δέ αὐτοῦ ἀπολογουμένου ὁ Φῆστος μεγάλῃ τῇ φωνῇ φησίν Μαίνῃ Παῦλε Τά πολλά σέ γράμματα εἰς μανίαν περιτρέπει)

Festus is speaking of learning as if it were a living thing that was turning Paul from sanity to insanity. If it would be helpful in your language, you could state the meaning plainly. Alternate translation: [You have become insane from learning so much]