Reflecting the cultural and regional diversity in China, signs may contain dialectal elements, especially those of the major dialects such as Cantonese, Min, and Shanghai/Wu. Dialects can differ in vocabulary and grammar, and particularly in sound. The differences in sound can sometimes be seen in phonetic transliterations. Dialectal words are those that do not have counterparts in the standard language. They are often written by borrowing standard characters just for the sound without regard for their original meaning (Rebus Principle); they can also be written in specially created dialectal characters. Dialects can also resemble classical Chinese, as they tend to retain features of older Chinese.