Musar for Sotah 60:23

We further have to keep in mind that the שירה, song, in our portion is introduced by the words: את השירה הזאת, "-in the feminine gender. This is peculiar in view of the fact that the corresponding song offered by the women under Miriam's leadership is addressed to להם, masculine. Why is Miriam's song not introduced by the words: ותען להן in the feminine gender? There are some linguistic experts who claim that the women never actually engaged in song, that they were not obligated to thank G–d in song but only played the drums and cymbals to give vent to their joy. According to these linguists, a number of Jewish men came to watch the women dance, whereupon Miriam called out to them: "Sing to the Lord, etc." Our sages reject this interpretation, saying that the women paraphrased Moses in their song.