This study presents a temporal co-registration method combining electromagnetic articulography (EMA) and electroencephalography (EEG) to capture the neural planning and execution phases of speech with high precision. Traditional EEG alignment based on acoustic vocal onset is often inaccurate due to the variable lag between articulatory and acoustic onsets. Our approach synchronizes EMA-derived speech kinematics with EEG data, addressing these challenges. We also examined the interaction between EMA and EEG systems, focusing on the integrity of EMA signals in the presence of EEG equipment and the electromagnetic influence of EMA on EEG signal quality. The method achieved a mean alignment delay of 2.7 ms (SD = 0.4 ms), enabling detailed analysis of pre-articulatory brain activities. Additionally, our evaluations confirmed the robustness of EMA signals and EEG event-related potentials, supporting the method's precision, feasibility, and reliability for speech planning research.