AFAIK the correct grammar for "speak slow" is "speak slowly" (slowly being an adverb). Please correct me if I am mistaken.

But in daily life I have not heard anyone saying "Speak slowlier".

I think I heard folks saying "Speak slower" but I also think it is incorrect.

Which is the best or correct form to convey the message?

Could that be the longish "Speak more slowly?"


5 Answers 5


Slow can be an adverb as well as an adjective. Not all native speakers know this, and some will tell you it's wrong to say 'Speak slower'. If you don't want to risk upsetting them, you can certainly say 'Speak more slowly'.

The Oxford English Dictionary has two citations for slowlier, including this from the seventeenth century philosopher Thomas Hobbes: 'They marched the slowlier for the rain which had fallen the same night.' It is, however, rare: I have never seen or heard it until now.

  • Your answer seems to be the most authoritative thus far (it actually brings citations). Accepting.
    – srf
    Aug 14, 2012 at 14:12
  • +1, but saying slow can be an adverb as well as an adjective might be somewhat confusing, if it gives the impression that you can use slow anywhere you can use slowly. You can't. I don't know the grammatical rules for when you can use flat adverbs (like slow), and I believe they're different in the U.S. and the U.K. Aug 14, 2012 at 14:49
  • @Peter Shor: I don't know either, but it may be that when 'slow' is an adverb it more frequently comes after the verb rather than before it, whereas 'slowly' can be in either position. Aug 14, 2012 at 15:19
  • +1 - and as a native English speaker, I've also never heard "slowlier" before.
    – Izkata
    Aug 14, 2012 at 18:02
  • glosbe: glosbe.com/en/en/slowlier
    – Kris
    Oct 11, 2018 at 5:41

Slower can either be an adjective, or an adverb.

"Speak slower" is grammatically correct. "*Slowlier" is not a word.

"*Slowlier" sounds very unnatural to a native English speaker; however, not all know that slower can also be an adverb.

Some incorrectly claim that the adverb "slower" should be avoided. However, it has been in use for about four centuries now and is well established as a real word.

  • Thanks +1 but please note @BarrieEngland's citations: Slowlier may be arcane but it does seem to be a word.
    – srf
    Aug 14, 2012 at 14:11
  • 3
    Albeit extremely uncommon. I have never heard it in spoken or written speech, and Barrie himself says the OED has only two citations for it, which are archaic. If it was ever used, it is archaic now. If you use it, be prepared to be corrected, rightly so.
    – Luke_0
    Aug 14, 2012 at 14:13
  • I don't suggest using it, but you have to be very careful in saying that something isn't a word. If you do, it's probably advisable to say what you mean by 'word'. Aug 14, 2012 at 14:22
  • 1
    @Luke: That's one way of defining 'word', but it's not the only way. The textbook definition, which is not itself without difficuties, is something like 'a unit of grammar that is more than a morpheme but less than a phrase'. Aug 14, 2012 at 15:16
  • 5
    I think "If you use it, be prepared to be corrected" is a pretty good practical definition.
    – tenfour
    Aug 14, 2012 at 17:10

People confuse everyday speech with what is grammatically correct. "More slowly" you say is "acceptable" but awkward? :DDD

More slowly is a grammatically correct option, as adverbs are formed in most cases from and adj. + -ly = slow >>> slowly.

Unfortunately most people form their opinion solely based on everyday speech, which can be accepted in conversation. However, many of those things are not grammatically incorrect.

In this case yes, both slower and more slowly are correct, but by no means is more slowly awkward.

Furthermore, someone mentioned near, nearly. Do not compare them as they do not have the same meaning, just like late-lately.

P.S. I have yet to hear a native speaker use few/little in the right context. I have met so many who use less for every example, even though the noun is clearly countable.

Do not search for your answers online, opinions are just opinions and what you hear everyday may not be grammatically correct. Consult the holy Bible of English grammar books "English grammar in use" by Raymond Murphy or Oxford Advanced Learner's Dictionary, the holy Bible of English-English dictionaries, or someone who has a Master's Degree in the English language and literature.

  • This would benefit from some supporting citations for your assertions. Jun 19, 2022 at 7:36
  • This appears to be largely commentary on other answers. Please take a moment to have a look at the Tour. Stack Exchange does not discuss: it's a site where questions are asked and concrete answers to those questions are given.
    – Andrew Leach
    Jun 19, 2022 at 8:18

Slower is a comparative adverb or adjective, depending on its sentence allocation. He talks slower than before. Slow/slowly can be both adverbs that have two forms. Like loud loudly, near nearly.


I am a native English speaker and I only use "slowlier". "Slower" would be incorrect and "more slowly" would be acceptable, but awkward.

  • I'm sorry, but this answer is just totally incorrect.
    – Marthaª
    Mar 20, 2014 at 14:59

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