[stan_rogers]

Grammar does differ, though, in subtle ways that don't necessarily impede communication but that mark the speaker for region. The participle gotten is probably the most prominent example; it is essentially unknown in most British English varieties and tense construction has more irregularities in British English than it tends to have in US English. (We Canadians speak both and neither, and nobody really knows the rules from day to day. They change on a pseudorandom sort of schedule covered by the Security of Information Act, and those in charge will neither tell us what's going on nor reveal their identities.)