  We present a detailed analysis of the cosmic string spectrum. Explicit
solutions are numerically found using Mathematica and presented here for the
lowest-lying supported modes. Most of the emphasis is on the Nambu-Goldstone
modes and the least massive excitation, the latter of which is shown to be the
scalar breather mode. We address the possibility of pseudoscalar excitations by
adding suitable interactions to the string and show that it is possible to have
a least massive pseudoscalar bound state with only bosonic fields. We finally
show how certain interactions in the bulk UV theory give rise to background
field interactions in the effective string theory.
