Well, this is a fascinating and somewhat thorny issue you have touched upon. The precise relationship between England and Ireland was a complicated one and obviously remains so to this day. Ireland has been seen by some historians as both the first and the last colony of the British Empire. Yet on the other hand, it is just as often omitted from wider British imperial history altogether. From an Irish Nationalist/Republican perspective a ‘colonial’ framework is the only proper way to understand the situation. Others would be considerably more wary in their usage of the term, arguing that it can give a misleading impression of Ireland’s past.

This is something that has been quite hotly debated within the historiography over the past number of decades. Some writers have sought to significantly complicate and question aspects of this proposition, while for some ‘colonialism’ remains a very useful rubric through which to understand Ireland’s past. Historical arguments such as these - as is so often the case - typically stem from conceptual debates: what exactly do we mean by ‘colony’, or ‘colonialism’? Accompanying this are debates surrounding chronology. If Ireland was an English/British colony, in what time period do we first situate this? How long was it a colony? When did it stop being a colony?

It’s an issue that remains unresolved, with many pretty much falling back on the concession that “it’s complicated”. Irelands position is a somewhat unique one, but even then, there is no such thing as the “ideal colonial form” against which the Irish case can be judged. As Joe Cleary has explained, the British Empire:

‘comprised a heterogeneous collection of trade colonies, Protectorates, Crown colonies, settlement colonies, administrative colonies, Mandates, trade ports, naval bases, Dominions, and dependencies’.

Following from this point, Kevin Kenny has rightly acknowledged that the:

‘relations of these constituent parts to the metropolis varied considerably across space and time and they followed divergent paths towards independence.’

For my part I would agree that we would indeed say that England "colonized" Ireland. In fact it seems preposterous to suggest otherwise, the difficulties usually arise when treating Irish history as a whole. The nature of English (and later British) government in Ireland, the attitudes towards the native population and the policies which followed on from this all broadly fit into a colonial model. In practice, for much of the medieval and early modern period, at least some parts of the country can accurately be described as a colony.

This colonisation dates back to the 12th century when English warlords seized extensive territories in Ireland. From that period on the English state sought to introduce measures that would bring the whole of the island under its control, most significant of these was the plantation and land settlement schemes you refer to. By the latter half of the 17th century Ireland was totally within the grip of the British Empire.

You state that you are “confident the common language…made it a very different situation than other examples of colonization”. Well of course it was a different situation that’s true. In some ways Ireland was anomalous, but you seem unaware that this common language (English) is not the native language of Ireland anymore than Spanish is of South America. Much like other instances of colonialism, the English/British state was concerned with the total eradication of the native culture, which they considered to be savage and barbarous, and it’s replacement with a society modelled in their own image. Of course this is different if we survey more recent history.

If I wanted to provide some further nuance then I might concur with Stephen Howe and speak in terms of Ireland exhibiting colonial features, but I think some of these arguments can miss the forest for the trees. Certainly there were contradictions and features which were unique to the Irish situation, certainly a number of things changed over time, but we could say this about any colonial situation. Reality does not tend to match neat theoretical definitions and I see no reason to throw the baby out with the bathwater, as it were, simply because of the obvious qualifications that we need to apply.

As Brendan O’Leary has put it:

‘at least some part of Ireland has conformed to the Oxford Dictionary definition of a colony for most of the time between the twelfth and the twentieth centuries, namely ‘a country or area under the full or partial control of another country’.

With that said, I’ll try and sketch out some of this in a bit more detail. And I have to make the usual caveat that I tend to write a hell of a lot when I get to answering a topic that interests me, so if you just skim it and want any particular clarification, or further detail, then by all means just ask. But since you asked the question, hopefully you are like me and are interested in a deep dive!