Is there anything wrong with this sentence?

[mallu]

I have known him criticize his teachers.- is this sentence wrong? Hope someone will tell me.
and this too
John discussed scratching oneself??/himself

[Daniel]

The first one is fine. It may be a little formal or archaic but it just means "aware that he did that in the past".

The second sentence has two different meanings depending on the word you use. "Himself" is specific (john) and "oneself" is general.

[ibarrere]

The first one is fine. It may be a little formal or archaic but it just means "aware that he did that in the past".

I have known him criticize his teachers.

Surely that's not grammatical for you, djr33? It needs a "to" in there for me:

I have known him to criticize his teachers

[Daniel]

Oh...  That "to" is so required that I imagined it was there while reading!

[mallu]

Isnt that 'to' optional? See the following sentence from Radford's book.

'I have never known Tom criticize anyone'- Isn't the above sentence like this?

[jkpate]

The sentence from Radford's book is also not grammatical -- you've found an editing error

[mallu]

Cant believe that,Can a celebrated author ,that too a native speaker go wrong like this? May be a dialectical difference,he is a brit & u guys r from states?

[Daniel]

Definitely an error/typo. It happens.

[ibarrere]

May be a dialectical difference,he is a brit & u guys r from states?

Definitely not. It's glaringly ungrammatical to the point that it wouldn't work in any dialect that I can think of.

[mallu]

Did anyone look at Radfords book.It is in section 3.6 titled Null T in infinitive clauses,He gives the following Examples there
a) I have never known Tom criticise anyone
b) A reporter saw Senator Sleaze leave Benny's Bunny Bar
c) You mustn't let the pressure get to you
Three examples of what he call bare (to-less ) infinitive.
P.S. It is not unusual cross-linguistically to omit  or keep a grammatical word optional in a dialectical variety of a language.isnt it?

[Daniel]

The other sentences are fine. It might be dialectal variation, but that is strictly ungrammatical in my American English. From context I agree that it looks intentional. Regardless that construction does exist with some verbs.

[mallu]

Is that verb or its perfect participle form which make the sentence ungrammatical?

[Daniel]

All ungrammatical:
*I have never known Tom criticise anyone
*I know Tom criticise anyone.
*I will know Tom criticise anyone.
*I knew Tom criticise anyone.

[ibarrere]

For comparison:

I have never seen Tom criticize anyone
?I see Tom criticize anyone
?I will see Tom criticize anyone
?I saw Tom criticize anyone

The last three examples aren't really ungrammatical, I just can't imagine anyone ever saying them.

[lx]

I have never known Tom criticize anyone

Brit here, grammatical for me.