A question about comparative adjective.
One I heard “it don’t matter” in a film, I searched and found out that it’s a variation of English named as “black English” or something like that, if I’m right.
Now I want to know whether there is “formaler” as the comparative form to “formal”, or the other forms of adding –er to make comparative adjectives, while in the Standard English it is considered to be grammatically incorrect.

Question

A question about comparative adjective.
One I heard “it don’t matter” in a film, I searched and found out that it’s a variation of English named as “black English” or something like that, if I’m right.
Now I want to know  whether  there is “formaler” as the comparative form to “formal”, or the other forms of adding –er to make comparative adjectives, while in the Standard English it is considered to be grammatically incorrect.

Answer

Sadly, there is no perfect rule.

Here are some general rules:

1. If an adjective has one syllable, we usually use -er: rich / richer.

2. Some two-syllable words also use -er: thrifty [careful with spending money] / thriftier. 

3. If an adjective has three syllables, we usually use "more": beautiful / more beautiful.

4. Also some two-syllable words can take  "more": candid [very honest]; more candid.

5. Finally, there are some adjectives that can take "-er" or "more": polite / politer; polite / more polite.

6. I suggest that you do two things:

a. Check a good dictionary.
b. Check the Web for lists of comparative adjectives.

7. Please remember: If a writer can use "-er" or "more," h/she will often make a choice based on sound. Some people think that "You are more handsome than I am" sounds smoother than "You are handsomer than I am." And, of course, some writers think that "handsomer" is better!

* I wish to credit a book called English Review Grammar by Walter Kay Smart.

Answer

Using "more" will always communicate the meaning, but it sounds strange for most one-syllable adjectives when forming comparative degree. A word like "formal", with two syllables, is borderline. I mean, it is not correct to use "formaler", but other two-syllable adjectives do use that structure, like "dirty" or "sunny". In case of three syllables or ending in "-ous", use "more".

Answer

The comparitave
                             for formal is  "more formal"

kind regards
Patrick