Which one is correct?

[nq:1]Hello, Could you please tell me which of the following are correct and which not? Slower,( used as an adverb), slowlier, more slowly and why? Thanks[/nq]
Slower is correct. Most monosyllable adjectives take "er" in the comparative form. Holy, holier. Full, fuller. Red, redder etc.

Slowlier is an attempt to add an adjectival suffix to an adverb (slowly). There is no such word as

[nq:1]Slowlier is an attempt to add an adjectival suffix to an adverb (slowly). There is no such word as slowlier. Just as there is no such word as reallier.[/nq]
You gave a good answer on all the choices.
"Slowlier" is not a preferred form, so a learner of English probably wants to avoid it, as many of us normally would. However, i must object to the suggestion that there is "no such word

[nq:2]Slowlier is an attempt to add an adjectival suffix to ... slowlier. Just as there is no such word as reallier.[/nq]
[nq:1]You gave a good answer on all the choices. "Slowlier" is not a preferred form, so a learner of English ... time. In fact, Google shows 10,400 hits. (I'm on a Google kick. It's such a great dictionary !) ER Lyon[/nq]
Clearly it gives you access to non-standard form

[nq:1]"Slowlier" is not a preferred form, so a learner of English probably wants to avoid it, as many of us ... many. I prefer "slower," but i hear or read "slowlier' from time to time. In fact, Google shows 10,400 hits.[/nq]
We still need a way of discriminating between correct English counted by Google hits and English errors similarly counted.

Reference to the rules of grammar help

[nq:1]Reference to the rules of grammar helps clarify this topic. 1. The comparative form of regular adjectives is made by ... 3. Adverbs usually end in -LY i.e. have two or more syllables, thus follow Rule 2 rather than Rule 1.[/nq]
What about "stupider"? I thought that was correct.

Maurizio

[nq:2]Slowlier is an attempt to add an adjectival suffix to ... slowlier. Just as there is no such word as reallier.[/nq]
[nq:1]You gave a good answer on all the choices. "Slowlier" is not a preferred form, so a learner of English ... "no such word." Any form in use is a word, even if it is disapproved or thought awkward by many.[/nq]
"Many" of us? Anyone who is "learning English" (and as

[nq:2]"Slowlier" is not a preferred form, ... However, i must ... or thought awkward by many. ... Google shows 10,400 hits..[/nq]
[nq:1]I accept your correction. I would add that it is not in common use, Google notwithstanding, and that it is clearly non-standard.[/nq]
Yes, it is a minority usage, but is used coherently by educated speakers to mean "more slowly." I found many of these usag

[nq:2]... i hear or read "slowlier' from time to time. In fact, Google shows 10,400 hits.[/nq]
[nq:1]We still need a way of discriminating between correct English counted by Google hits and English errors similarly counted.[/nq]
Saving the issue of "correctness" for later, i agree with your point. I found this fascinating enough to look at about a hundred Google citations for "slowlier" (a

[nq:2]"Slowlier" is not a preferred form, so a learner of English probably wants to avoid it, as many of us normally would.[/nq]
[nq:1]"Many" of us?[/nq]
I take it "many" sounds too modest to you. It can suggest anything from a fairly large minority to a significantly large majority, and can be misleading unless the context clearly disambiguates it. I will allow that it is a fair majority

[nq:1]What about "stupider"? I thought that was correct.[/nq]
It's as common as "more stupid" according to Google. I don't find it objectionable, certainly not "incorrect." Whether you use it depends on whom you wish to please. Some people might find it objectionable because there are few pleasing things you can say with the word. But not because it is incorrect.
ER Lyon