In this paper, a robust and blind speech watermarking technique is proposed using a combined scheme based on discrete cosine transform (DCT) and discrete wavelet transform (DWT) Algorithms within signal sub-sampling. To achieve good imperceptibility, hybridization is implemented against many attacks such as: re-quantization, cropping, echo, amplification and additive white Gaussian noise (AWGN). We profit from the advantages of correlation between two successive samples so that we used signal sub-sampling. Obtained results, compared successfully to recent researches, show the robustness of our proposed approach.