In recent years, Cheng has also begun to write songs in Mandarin. They include several poems written by the late legislator Lu Hsiu-yi, that Cheng was invited to set to music. When the songs were premiered at Taipei's Novel Hall on 1 March 2002, everyone in the audience was deeply touched, and Lu's widow, Council for Cultural Affairs chairwoman Tchen Yu-chiou, was moved to tears.
近年來鄭智仁也開始寫作國語歌，其中他也受邀將已故立法委員盧修一寫的詩詞譜成曲子，今年三月一日在台北新舞台首度發表，現場聽者無不動容，盧修一的妻子、文建會主委陳郁秀也深受感動而落淚。