syntactic

syntactic:
 * definition**: concerning or obeying the rules of syntax. **adj** (Longman Dictionary of English Language and Culture 2004)

eg; 'Be' and 'become' are often used in the same way syntactically.

Context Sentence:This is evidence of syntactic differences, i.e., the kinds of grammatical constructions we use.

Source: P76, //Language, Society and Power An introduction//