In error analyses using sentence repetition data, most authors focus on word types of omissions. The current study considers serial order in omission patterns independent of functional categories. Data was collected from Russian and German sentence repetition tasks performed by 53 five-year-old bilingual children. Number and positions of word omissions were analyzed. Serial order effects were found in both languages: medial errors made up the largest percentage of errors. Then, the position of omissions was compared to visuo-verbal n-back working memory and non-verbal visual forward short-term memory scores using stepwise hierarchical linear regression models, taking into account demographic variables and receptive language. The interaction differed between languages: there was a significant negative association between omissions in the medial position in German and the final position in Russian and the visuo-verbal n-back memory score. Our study contributes to the understanding of how working memory and language are intertwined in sentence repetition.