All sources from this era have been collected and published, usually in the series Estrikken of the Frisian Institute of the Rijksuniversiteit Groningen. The Frisian Academy stored all the material digitally in the Language Corpus 'Middle Frisian'. The corpus has almost completely been lemmatised. All words are connected to their dictionary entries, which thus subsume complete paradigms. Various spellings of the same words have also been subsumed under one entry.

The corpus contains half a million tokens of about 80.000 word forms of 21.000 lemma's. Frisian material which was not yet known has recently been published as Frysk fan 1550 oan 1801, edited by Philippus Breuker, Estrik/Ålstråk 82, Groningen/Kiel/Leeuwarden, 2008. The Burmania collection of proverbs (1641) has been analysed by Frits van der Kuip and published as De Burmaniasprekwurden (Leeuwarden2003).

The corpus contains both the texts and a search program for words and word forms. Two search possibilities allow the user to access a Middle Frisian word in its context: the Middle Frisian word form or the New Frisian lemma. The user also gets an overview of the various spellings and of the paradigm to which the search word belongs. People have to register (which is for free) before they can actually use the language corpus. In order to register, follow the instructions at de taaldatabank. In case there is a problem, contact Arjen Versloot.

Texts written in the dialects of Hylpen (Hindeloopen), Molkwar (Molkwerum) or Skiermûntseagersk (Schiermonnikoog) have been collected in a separate corpus referred to as 'Dialfoar1800'. Study of Middle Frisian has yielded a list of localised authors and texts. Some texts are anonymous, but they could still be localised by analysing either the  content or the linguistic characteristics. Below we present this list. Next to it is a map, by way of illustration of the type of historical dialect research which the Corpus Middle Frisian makes possible.