Comparative linguistics offers valuable and sometimes unexpected perspectives into the workings of languages. Comparisons between unrelated languages unsurprisingly can provide novel insights into how a particular function can be manifested in greatly contrasting ways throughout the languages of the world. At the same time, comparisons between closely related languages, while at first sight apparently less dramatic than those between unrelated languages, often also make for startling revelations and insights. Although a two-way contrast is a sufficient basis for a solid comparative study, it is the addition of a third language into the mix that really starts to add interest. In particular, the view of a three-way comparison as a “sandwich” in which the language in the middle interfaces with a language at either side presents one with new and vital perspectives on all three languages.

Within the realm of Germanic linguistics, the use of this sandwich model as a basis for three-way comparisons has been at the forefront of research for over a decade now. For instance, the “Germanic Sandwich” conference series celebrated its fifth edition at the University of Nottingham last year, with previous editions having been held in Berlin (2005), Sheffield (2008), Oldenburg (2010), and Leuven (2013).Footnote ¹ Initially, the primary focus was the West Germanic sandwich in which Dutch stands between English and German. This research built on the work of van Haeringen (Reference Haeringen1956), who summed up the starting point of his seminal investigation by referring to the Dutch language thus:

As noted by Vismans et al. (Reference Vismans, Hüning and Weerman2010:298), van Haeringen's focus on grammar and morphology was expanded upon by the contributors to the first Germanic Sandwich conference—as demonstrated by the contents of Hüning et al. Reference Hüning, Ton van der Wouden and Verhagen2006, which collected papers presented at that conference—to encompass all corners of linguistics, and many different theoretical and methodological perspectives. In terms of languages covered, too, there has been expansion: van Haeringen's original trio of Dutch, English, and German, while still the focus of much interesting and revealing research, has been further expanded, with the sandwich model being applied in innovative ways to other combinations of Germanic languages (and, indeed, sometimes incorporating a non-Germanic language).

This special themed issue of the Journal of Germanic Linguistics builds upon existing publications, such as Hüning et al. Reference Hüning, Ton van der Wouden and Verhagen2006 and JGL 22.4, to showcase the further evolution and expansion of the sandwich model—and demonstrate the model's continued validity—and to present the state of the art in research within comparative Germanic linguistics. There are five papers in this issue, all of which take the sandwich model in interesting and new directions. Hoekstra introduces Frisian into his study of finite verb doubling; focusing on Dutch, English, and German, Poortvliet explores evidential meanings in verbs of appearance; Lin investigates verbs of necessity; de Hoop et al. study comparative markers, and Leuschner et al. address V1-conditionals. Accordingly, the papers presented in this volume not only provide novel insights and show new directions in comparative Germanic linguistics; they also apply the sandwich model to topics previously not handled in this way.

I am grateful to the contributors to this special themed issue (and, indeed, to all participants of the 2015 Germanic Sandwich conference), and I would also like to thank the editor of the JGL Tracy Alan Hall for advice and guidance right from the earliest proposal for this issue, as well as the colleagues who peer-reviewed the contributions to guarantee the excellence of the research presented here.