Understanding of predicates and reflexives was explored in children who stutter (CWS) and children who do not stutter (CWNS) who were between 9 years, 7 months and 10 years, 2 months. Demands on working memory and manual reaction time were also evaluated in two experiments that used a four-choice picture-selection sentence comprehension task. CWS were less precise than CWNS on the attachment of predicates. For reflexives, there was no between-group difference in precision, but there was a difference in speed. The two constructions provoked processing at diverse points on a speed–accuracy continuum with CWS sacrificing precision to reply fast with predicates, while they preserved precision of reflexives by replying slower relative to CWNS. Predicates made more demands on language than nonspeech motor reaction time, whilst the reverse was the case with reflexives for CWS compared to CWNS.