This paper focuses on a newly developed transparent nADPCMB/spl perp/MLT speech coding algorithm. Our coder first decomposes the narrowband speech signal in subbands, a nonlinear ADPCM scheme is then performed in each subband. The signal subband decomposition is piloted by the equivalent Modulated Lapped Transform (MLT) filter bank. The novelty of this algorithm is the nonlinear approach, based on neural networks, to subband prediction coding. The nADPCMB/spl perp/MLT coding algorithm derives from our preceding nonlinear speech coding algorithm and our ADPCMB/spl perp/MLT linear subband coding scheme. The nADPCMB/spl perp/MLT coding algorithm also reveals transparent coding of a multi-talker speech signal at the rate of 24 kbps.