Adjective Order and Commas? Do we need commas in these situations?

Question

I'm a Canadian English speaker trying to review my grammar on coordinate and cumulative adjectives. I know the conversational or natural rules by heart, but I need to teach the rules for writing to my ESL students, so I'm giving myself a refresher on the grammar and punctuation for writing. From what I understand so far:

1. Coordinate adjectives modify a noun equally. Therefore, it doesn't matter what order these adjectives go in. These adjectives are also usually separated by a comma. For example, "the dangerous, exciting game" can be said as "the dangerous and exciting game" or the "exciting and dangerous game" or the "exciting, dangerous game", because these are all matters of opinion and therefore are all equally describing the noun. I'm using the Grammar Girl article for reference to this rule, as well as Michael Swan's Practical English Usage:

Before nouns, we generally use commas between adjectives (especially in longer sequences) which give similar kinds of information, for example in physical descriptions.

a lovely, long, cool, refreshing drink (Swan, Practical English Usage, p. 9 )

2. Cumulative adjectives, however, do NOT modify a noun equally. They are what we call "stackable". Therefore, we usually do not use commas between them. For example, the old German automobile. (We cannot say the German, old automobile). Again, here is the Grammar Girl article on the order of adjectives. Note the lack of commas in the examples:

For example, the beautiful Turkish rug sounds right and the Turkish beautiful rug sounds quite wrong. And the white marble tile definitely sounds better than the marble white tile.

In my search for good practice materials for my students, I came across this ESL Library post( now ELLII), where one of the examples given was :

- I live in the big, red house down the street. (I live in the big and red house; both big and red describe the noun house.)

Why is there a comma here? To the best of my knowledge, big and red cannot be switched, and they don't equally modify the noun "house".

Also, if you scroll further down, there are more examples:

1. My friend is a talented, young musician. (opinion, age)

2. That car is a beautiful, older, Italian model. (opinion, age, origin)

3. I bought a shiny, small, square, metal vase. (opinion, size, shape, material)

4. We browsed through the many antique, colorful, silk dresses in the boutique. (age, color, material)

Why are there commas here? To the best of my knowledge, these adjectives are not from the same categories and they cannot be switched around. Is there an explanation for this? At first glance, I am inclined to think the website is incorrect. Or maybe I'm missing something obvious? Please advise me.

Answer 1

With adjectives of equal value (can be reordered without consequence), you put a comma between them. You omit the comma between adjectives of non-equal weight. For example:

He was a talented, young musician.

The two adjectives are of equal weight and could be reversed:

He was a young, talented musician.

Therefore you use a comma.

We browsed through the many antique, colorful, silk dresses in the boutique.

"antique", "colorful" and "silk" are all equal, so their order doesn't matter and they require commas

"many" is not equal to the others and therefore does not require a comma and cannot be reordered

Here's a reference for the downvoters:

Commas between two adjectives

Regardless of whether you think this is an official rule, it works and is an easy way for non-English speakers to quickly arrive at the right answer.