We have seen that Adjectives generally precede Nouns (ATTRIBUTIVE POSITION) while Adverbs often, but by no means always, follow Verbs. If there are several Adjectives, their order is fairly fixed. We would normally say
but not
27b. * a yellow old silly hat
These rules show the importance of word order in English. Competent speakers produce the right order without thinking about it, but order can cause problems to learners of a language, especially if the rules for their own language are different. In French, for instance, the Adjective usually comes after the Noun. There are some expressions like this in English, borrowed from French after the Norman Conquest of 1066 AD:
These examples make another important point: every rule has exceptions. This is particularly true of English grammar, which is flexible enough to allow subtle variations in meaning. In the right context you could probably argue that the order of (27b) is acceptable, or argue for other acceptable permutations.