Original: Some composers, such as Mikhail Glinka, Alexander Serov, Rimsky-Korsakov, Puccini, and Mascagni wrote passages of music without text and subsequently had the librettist add words to the vocal melody lines.
Simplified: Composers, such as Mikhail Glinka, Alexander Serov, Rimsky-Korsakov, Puccini, and Mascagni all did this sometimes.