Thank you for taking the time to read and answer my question. I very much appreciate it. I understood that the basic answer to my question was that if the lyrics are not vulgular, ’and the thoughts expressed in it do not lead you to improper thoughts, then it is permitted’. Would it be possible to obtain a source for this answer? I would realy appreciate it. Thank You.

Shalom, I am glad that my answer to you was a help. In connection to sources - I am not certain which sources exactly you are asking for. The content of the response I wrote you is not a direct quote from any one source, but rather my humble opinion based on the Torah that I have merited to learn over the years. However I can send you to see the Talmud in Shabbat 33a for a primary source about "nivul peh" (impure speech) and to the Shulchan Aruch, Orach Haim, 307, 16 (and the commentators there) for a discussion of improper content. Also see the Gemara in Avodah Zarah 20b about improper thoughts during the daytime leading to sin at night (and the Tosafot there). Blessings, D. Sperling