This article suggests a method to deal with cross-linguistic differences in children with Specific Language Impairment. The differences in vulnerable structures reflect typological properties of the surrounding language (e.g., Leonard 2014a, 2014b). This article adds a developmental perspective to the discussion by interpreting the vulnerable structures through the framework of Processability Theory (PT; Pienemann 1998, 2015) and placing them along a developmental continuum. Studies focusing on production of grammatical structures in children with SLI from 19 different language backgrounds are examined. The results of the analyses suggest that the major grammatical problems in children with SLI belong to the later stages of the PT hierarchy. PT gives an alternative interpretation to earlier accounts by offering a developmental perspective and a metric that allows us to measure both languages in bilingual children.