This article studies three measures of phonological working memory as tools to identify SLI children: word repetition, nonce word repetition, and digit memory. We propose that a deficit in the phonological loop causes a delay in the acquisition of lexicon, morphosyntax, and discourse. In this research we try to find out whether the scores in these three measures correlate with language performance in SLI and normally developing children. We run tests of word repetition, nonce word repetition, digit memory, and language tests on lexicon and morphosyntax. We found that SLI children scored lower than normally developing children in word, nonce word repetition, and digit memory for all age groups. Scores of the tests show that these can differentiate SLI and normally developing children for all age groups. The results of this research suggest that processing limitations may increase the language difficulties of SLI children.