interpolation

US /ɪnˌtɝː.pəˈleɪ.ʃən/
UK /ɪnˌtɝː.pəˈleɪ.ʃən/
1.

phép nội suy

the addition of something different in the middle of a text, piece of music, etc. or the thing that is added:

:
An actor reads the poems in English translation, with brief musical interpolations.