You would expect deviations from Standard English to simplify things: they are likely to omit final consonants, drop suffixes, and so on. But sometimes one finds the opposite. Take this sign I saw on the door of a shop in Bandar Seri Begawan, the capital of Brunei.
Note the spurious 'd' on the end of 'closed'. Perhaps one could regard this as a case of hyper-correction: the user is so concerned about omitting suffixes that a 'd' is added here even when it is not needed.