frawjōn

• "it doesn't really resemble Old English": even my quote didn't say it was Old English, did it? If you want to bring hwat/wat, I can bring hic/ic, the latter is a hypercorrection according to all interpretations I know (but I don't know many). Someone writing Latin (and using the continental alphabet), trying to learn Old Kentish is an alternative. Http://lyrics.wikia.com gives many examples of people trying to write down the lyrics of songs in foreign languages, many of them include a(n attempt at) translation.
• "Wachtendonk Psalms": I only quoted en.wikipedia, but if you ask, I don't think "Old High German" did exist as a language either. Lack of w:High German consonant shift doesn't mean much, w:Attila did shift to Etzel in the w:Nibelungenlied. Some 40 years ago, I realized as a child that Limpurg (in e.g. w:Van Rechteren-Limpurg) is a bekakt pronunciation of Limburg. If kids speaking neighbouring dialects notice that, it doesn't distinguish languages, but sociolects.
• "Leiden Willeram", writing 'z' for a /t/ at some places doesn't look Old Dutch to me.
• "Rhinelandic Rhyming Bible", indeed, even today the local dialects have Brabantic and Low German features, which makes claiming a separate "Old Dutch" language a millennium ago somewhat farfetched.

I am implying that none of the Late Western Germanic dialects and jargots was Old Dutch (several of them had some of the features ascribed to Old Dutch, none of them had all) and that only after the rise of the Burgundians in the Southwestern Netherlands (and the subsequent w:Dutch Republic) the need to construct such a language arose.

• Old Kentish is a form of Old English, so yes you did imply that even if you weren't aware of it. As for hic/ic, that is the kind of hypercorrection you'd expect from a speaker who no longer pronounces the h- in other words. And it just happens that that is a feature typical of West Flemish, where h- was lost, and g- became h-. That feature is still apparent in West Flemish today. I don't see where Old English comes into that though, as it was ic there all the same.
• I didn't say the z did look Old Dutch. But scholars have realised that it's just a respelling of t following the Old High German norms. That much of it is OHG in origin, at least. However, as the Wikipedia article also mentions, there are words the text that, despite their High German-influenced spellings, are clearly Dutch words as they are foreign to Middle Central German but found in Middle Dutch texts.
• I don't understand what you mean by separate language, exactly. Nobody was claiming that Old Dutch is separate, as such. Continental West Germanic has always formed a dialect continuum and still forms one today, if you look past the standard languages. Linguists draw lines between the dialects according to certain defining features, but those definitions are arbitrary, just as the distinction between, say, Middle and Modern English is arbitrary. But that doesn't mean there isn't a definition of what Old Dutch is, or isn't. So I don't understand why you are arguing that no definitions exist, when they clearly do.

But if you really insist on arguing that Old High German, Old Dutch and Old Saxon aren't to be considered languages on Wiktionary, I invite you to nominate Category:Old High German language, Category:Old Dutch language and Category:Old Saxon language for deletion.

• The Cantware weren't Anglish. When you claim "still apparent in West Flemish today", I would appreciate some sources that West Flemish had h-deletion at the time, because it also happens that Kentish lost h-. Some of the dialects I speak, don't pronounce "h-" either, but I wouldn't write "hik" (unless for a hiccup). Considering ellærn#Old English and Holunder#German, some dialects of Old English had already dropped h- in some words.
• But why would one only write 'z' for 't' at some places? Especially when those places often coincide with the High German consonant shift, I would expect a High German speaker (or at least a High German writer). Nicoline van der Sijs says "Daarbij heeft hij sommige woorden in het Oudnederlands omgezet, andere in het Oudhoogduits laten staan", though she expects a spreaker of Dutch. That's not very solid ground on which to build the hypothesis of a separate language.
• Oh yes, there is a definition of Old Dutch, it's every piece of Late West Germanic which can't be proven to be another LWG dialect/language (een deel van de woorden is dat wel, of in ieder geval kan niet bewezen worden dat ze het niet zijn).

I admit that Old Dutch, Old Saxon and Old High German can be considered three languages, I just consider the distinction anachronistic. You seem to group dialects as a language based (too often, IMHO) on current political borders (like Old Dutch isn't Old German, but Old kentish is Old English). One can file "urov", "urowen", "uruwen", "urowen", "urowe" and "fruwe" as frouwa, but preferring the starting 'f' (over 'u'/'v') seems like rolling with a loaded dice to me.