Using naturalistic data from four children (00;10 to 02;06 years old) and experimental data from 60 children (4 to 8 years old) and 15 adults, this inquiry suggests that Mandarin speakers’ evaluation about the scope assignment between negation and universal quantification is attributed to the interplay of various influential factors: word order, lexical semantics of logical expressions, structural complexity, conversational implicature, and felicity in the use of negation. Knowledge about the crucial importance of word order in the grammar of Mandarin-speaking adults is not initially present in the grammar of children, but is gradually learnt. They initially rely excessively on lexical semantics in interpreting scope, sometimes leading to non-adult interpretations. Full mastery of scope knowledge comes when they become fully aware of the prominent role of isomorphism, at age 6 or 7.