Speak slow or speak slowly.

[hirashin]

Which would you say in each set.
1A) Go slow.
1B) Go slowly.
2A) Drive slow.
2B) Drive slowly.
3A) Speak slow.
3B) Speak slowly.
4A) Talk slow.
4B) Talk slowly.

Hirashin

 

[WonkoTheSane]

All B.

Except 2 if you're describing the drive, as in "The drive was slow."

 

[hirashin]

Would "Speak as slow as you can" be wrong ?

 

[WonkoTheSane]

Would "Speak as slow as you can" be wrong ?

It should be slowly to my ear. The other way sounds lazy and incorrect.

 

[hirashin]

Thanks, Wonko. I have a feeling that I have seen a sign saying "School Ahead Go Slow". Is it a strange way to use "slow"?

 

[Lothor]

Thanks, Wonko. I have a feeling that I have seen a sign saying "School Ahead Go Slow". Is it a strange way to use "slow"?

Evidently not.
go slow sign - Google Search

 

[joadbres]

"Slow"/"slowly" is one of those adverbs that is a bit special, due to its history.
Check out this video for an explanation:
Drive Safe: In Praise of Flat Adverbs (Video) | Merriam-Webster

I would say that "slowly" is the preferred form in all of the examples in the original post, but it is difficult to justify "slow" as being completely wrong.

 

[johnnyG]

OTOH, you could speak low:

 

[hirashin]

Thanks for the help, everyone. "Go slow" is a special case, it seems.