As mentioned in Chapter 1, this study aims to provide a descriptive and historical account of some of the most distinctive features of HE grammar. In order to fulfil its objectives, this study is corpus-based, i.e. the discussion draws as much as possible on data obtained from sources representing actual HE vernacular as it is spoken today and, insofar as data are available, in its past forms. The primary data come from a tape-recorded corpus of present-day HE speech. The composition and nature of the material is described in section 4.2.1; the following section (4.2.2) provides an outline of the linguistic situation in the dialect areas represented in the HE corpus. The earlier stages of HE grammar are examined on the basis of a variety of sources, including manuscripts and literary or other texts depicting earlier forms of HE vernacular. The former consist mainly of letters written by Irish people in the eighteenth and nineteenth centuries. An account of the early HE sources and their usefulness is given in section 4.2.3.
Because of the often complicated nature of the issues relating to the origins of HE features, no single source is adequate to provide the evidence needed; therefore, I have had to compile, or make use of, databases or corpora representing other than Irish varieties of English. The earlier stages of (English) English form an important point of comparison, and for that purpose I have used the diachronic part of the machine-readable Helsinki Corpus of English Texts (see section 4.3.1 for details and discussion of the limitations of this corpus). Another essential aspect is the possible use of similar syntactic features in present-day British English (BrE) dialects. To complement the picture obtainable from the rather scant literature on this area, I have compiled machine-readable corpora and databases from some existing sources comprising a number of BrE dialects. These are described in detail in section 4.3.2. A third point of comparison is formed by the varieties of English spoken in the other Celtic lands, most notably in certain parts of Scotland and Wales. The data from these varieties, here collectively termed ‘Celtic English(es)’, are introduced in section 4.3.3. Finally, comparisons will of course be made throughout the study on the basis of existing literature with many other varieties which display the feature or features at issue and are therefore relevant to the discussion. Scots, Scottish English, and American English are examples of this category.