Don’t forget about names like:
- Mathias d’Arras
- Martin Luther King, Jr.
- Hector Sausage-Hausen
This should do the trick for most things:
/^[a-z ,.'-]+$/i
OR Support international names with super sweet unicode:
/^[a-zA-ZàáâäãåąčćęèéêëėįìíîïłńòóôöõøùúûüųūÿýżźñçčšžÀÁÂÄÃÅĄĆČĖĘÈÉÊËÌÍÎÏĮŁŃÒÓÔÖÕØÙÚÛÜŲŪŸÝŻŹÑßÇŒÆČŠŽ∂ð ,.'-]+$/u