Micro Raman spectra for (Ta 2 O 5 ) 1 - x (TiO 2 ) x reveal an induced Raman enhancement of the low frequency phonon modes for a critical TiO 2 content, x = 0.08. The temperature and pressure effects on these modes have also been studied. The Raman enhancement is shown to be associated with effects of the superstructure which is composed of TiO 6 octahedra and Ta-O clusters. Pressure Raman scattering on (Ta 2 O 5 ) 0 . 9 2 (TiO 2 ) 0 . 0 8 indicates that a phase transition occurs at ∼ 6.22 Gpa. Based on our Raman scattering studies, the origin responsible for the enhanced dielectric constant in samples with TiO 2 , content, x = 0.08, has been provided and discussed.