Legal Question in Intellectual Property in California

Re: Use of my music by others

I am both an experienced entertainment attorney and a musician, so I can relate to your problem!

It depends what your agreement with your co-songwriter is. For example, you can fill out copyright applications to split the rights in any percentage you wish.

There are also rights of attribution or mis-attribution, which touch more on trademark and unfair competition.

Let me know if I can be of further assistance.

Re: Use of my music by others

The short answer is: yes, probably so. Without seeing the documentation of the relationship between the two of you (i.e. your contract/s with each other), it would be impossible for me to give you specific advice. However, I can provide some information on how copyright works.

Generally speaking, if more than one person contributes to a work and each person's contribution is discernable (i.e. one writes music and the other lyrics), each of those people owns the part that embodies his/her contribution.

(On the other hand, where the work is not divisible, as in a script, each owns a portion according to a percentage the parties agree on.)

Where more than one person owns a copyright, any of the owners can legally exploit (that is, license, sell, use, copy, etc.) the copyright, with or without the other owners' permission, but the proceeds must be shared according to the amount of ownership interest. For instance, if the agreement is that copyright ownership is shared 60/40, any payments received are split that way.

In the case of music, the composer has the right to control the use of his/her music, and the lyricist has the right to control his/her lyrics, unless there is a written agreement to the contrary.

From the circumstances you describe, it is likely that your partner has the right to continue to use the song as written (provided you get paid, of course), but most likely does not have the right to use the music with new lyrics. You do say, though, that your partner wrote "the melody" which complicates matters somewhat, because it raises the question of who wrote the music. (In most cases, the melody is considered "the music.")

The best way for you to get a useful answer to your question, and preserve your rights, is to consult with a competent music attorney who can look at all the facts and review contracts between you and your partner.