Spectral line shapes of ions in hot plasmas submitted to a strong oscillating electric field have been theoretically studied by applying standard hypotheses of plasma line broadening along with a nonperturbative (Floquet) treatment of the (external) oscillating field. The formulation has been applied to the two first resonance lines of various hydrogenic ions in hot plasmas subjected to a strong Langmuir oscillation or submitted to an intense laser field. It is shown that the simultaneous action of a strong oscillating field and the plasma particle fields can lead to large modifications of the spectral line shapes.