Legal Question in Intellectual Property in Texas

Re: Time limitation on song copyright

The current copyright term for individual authors/composers is for the life of the author plus 75 years (75 years after the author's death). There are different terms for many musical compositions from the early part of the 20th century that may or may not still be in effect. If the music is from before 1900 then it is most likely public domain. If the music is from after 1976, then someone will still likely own the copyright even if the composer is now dead.

As for using lyrics in a novel, then it could be considered "fair use" if it is incorporated into a story plot and not all of the lyrics are used e.g., like someone quoting a line or two from a song. Fair use is a very gray area, but if it otherwise qualifies, you would not need permission, but you might have to attribute (tell who the writer of the lyrics is if known).