I just took a quick look in the BNC to see what basic corroborating evidence (if any) I could see. Only searching for "never known him" (too lazy to look up the notation of accusative pronouns in their syntax) and there are only 16 results in total:
1 B20 W_fict_prose A B C It's a matter for the emperor, of course, but I've never known him refuse a name so recommended.' Thiercelin still could not think what he
2 C8E W_fict_prose A B C It was certainly bizarre, Uncle Anwar behaving like a Muslim. I'd never known him believe in anything before, so it was an amazing novelty to find him
3 C8S W_fict_prose A B C n't need me any more. Grgoire doesn't need me. I have never known him so happy.' She was then eighteen; serious, intense, and
4 FEE W_fict_prose A B C he be doing? Round about four o'clock he did a thing I'd never known him do since I got there -- he started to play his guitar. He
5 FRC W_fict_prose A B C family to be separated.' She sniffed emphatically.' But we have never known him. He was Mummy's only brother and they drifted apart.' She
6 G07 W_fict_prose A B C him to send that letter). It was a job. I've never known him in such a huff. Wouldn't he call it a day, and
7 GW3 W_fict_prose A B C sponger, or nasty with it?' Curtis hesitated.' I've never known him do anything vicious, though in drink he sometimes talks big. Usually he
8 GW8 W_fict_prose A B C . From the grave he could make a girl like her, who had never known him, feel extremes of emotion. She sat in a quiet, dark corner
9 GWB W_fict_prose A B C off...' And he didn't come here?'' I've never known him come here until today.' Wycliffe was looking back down the slope,
10 H7W W_fict_prose A B C shudder inwardly.' How on earth did you hook him? I've never known him go for the skinny boyish type before.' She sighed indulgently, but
11 HWL W_fict_prose A B C Never know till I call,' Lewis shrugged.' But I've never known him closer than a mile to a pick-up. He's careful that way.
12 HXG W_ac_soc_science A B C : 179; in Scheurweghs 1959: 240) (109) I had never known him ask a favour of this kind before. (Snow 1961: 25;
13 HXG W_ac_soc_science A B C the operative sense followed by the to infinitive: (110) I've never known him to lie to me. (O'Neill 1934: 39; in Visser 1973
14 HXG W_ac_soc_science A B C construed with to in British English as well: (112) I had never known him to pass the garden-gate before. (Dickens 1850: 127; in Jespersen
15 HXG W_ac_soc_science A B C say, " I always get what I want from him. I've never known him to fail. (Thurston 1909: 4; in Kruisinga 1931: 241
16 EC8 W_non_ac_humanities_arts A B C endure when aristocracies crack and proletariats crumble. In our own land we have never known him, but till we create him our land will not be a nation.
Some (red) without
to, others with it, and one interesting quote in blue that looks like it might even be an explanation of the difference, which would be a nice coincidence if that turns out to be true. I would accept both versions, the one that sounds more normal is the one with 'to'. It has the same distinction as the bare verb form in subjunctive-
that clauses.
It's a requirement that she come to work on time.
It's a requirement that she comes to work on time.
People say both in ordinary speech, but the one with -s sounds more ordinary (as does the version of 'never known him' with 'to') but the original one still sounds correct. To me, anyway. The difference is of formality, though I can accept some examples in that list do sound a bit strange and wouldn't be anything I'd say. Some forms of that syntax (including the one mallu posted) are just formal sounding, not ungrammatical to my ear. It does sound a lot better with a pronoun than a full NP though, which usually signals a feature on its way out of the language or structurally unsound (where many syntactic features remain with pronominal uses after full NP uses have started to fall away out of the syntax, like V2). Okay, now I've reached the point where I can't judge it objectively anymore. Cool to see such different opinions on it though. I'm not surprised it's felt to be ungrammatical for non BE speakers.
Found the updated POS-syntax if anyone else fancies a gander -
known [pp*] [vv0*] (known + pronoun + bare infinitive)
Radford mentions this form in many of his books, so it rules out the chance of it being unintentional.
In "Minimalist Syntax: Exploring the Structure of English" he uses the example "I have never known [him tell a lie]" as an example. Then in "English Syntax: An Introduction" he uses the sentence quoted on the last page about Tom. In another book (Analysing English Sentences: A Minimalist Approach) he has the example, "I've never known there be complaints about syntax." In Syntactic Theory and the Structure of English, the Tom example is used again etc. etc.
WebLearnEng also has something to say on their site about it:
The verb word “to know”, when it means ‘to see’ or ‘experience’, may be followed by an infinitive with or without ‘to’:
e.g.
I have never known him make a mistake.
or
I have never known him to make a mistake.
Just putting it out there before any potential tacit assumptions are made about my ability to English!
