Registers show grammatical variation. That is, they differ in their use of certain grammatical structures. In English for example, different registers show high variability in the occurrence of sentence-final prepositions:
Thatís the teacher I was telling you about vs. Thatís the teacher about whom I was telling you.
Studies into register variation have shown that there is usually a characteristic difference between spoken and written registers concerning the use of sentence-final prepositions:
An example: some syntactic features characteristic of legalese (the register of the legal profession):
(Information taken and adapted from Finegan, 2004)
(See also Semantic Markers for more information on the typical features of legalese).