We present an extension of the Low Saxon Universal Dependencies dataset and discuss a few annotation-related challenges. Low Saxon is a West-Germanic low-resource language that lacks a common standard and therefore poses challenges for NLP. The 1,000 sentences in our dataset cover the last 200 years and 8 of the 9 major dialects. They are presented both in original and in normalised spelling and two lemmata are provided: A Modern Low Saxon lemma and a Middle Low Saxon lemma. Several annotation-related issues result from dialectal variation in morphological categories, and we explain differences in the pronoun, gender, case, and mood system. Furthermore, we take up three syntactic constructions that do not occur in Standard Dutch or Standard German: the possessive dative, pro-drop in pronominal adverbs, and complementiser doubling in subordinate interrogative clauses. These constructions are also rare in the other Germanic UD datasets and have not always been annotated consistently.

We investigate the usage of auxiliary and modal verbs in Low Saxon dialects from both Germany and the Netherlands based on word vectors, and compare developments in the modern language to Middle Low Saxon. Although most of these function words have not been affected by lexical replacement, changes in usage that likely at least partly result from contact with the state languages can still be observed.

We present lemmatization experiments on the unstandardized low-resourced languages Low Saxon and Occitan using two machine-learning-based approaches represented by MaChAmp and Stanza. We show different ways to increase training data by leveraging historical corpora, small amounts of gold data and dictionary information, and discuss the usefulness of this additional data. In the results, we find some differences in the performance of the models depending on the language. This variation is likely to be partly due to differences in the corpora we used, such as the amount of internal variation. However, we also observe common tendencies, for instance that sequential models trained only on gold-annotated data often yield the best overall performance and generalize better to unknown tokens.

We compare five Low Saxon dialects from the 19th and 21st century from Germany and the Netherlands with each other as well as with modern Standard Dutch and Standard German. Our comparison is based on character n-grams on the one hand and PoS n-grams on the other and we show that these two lead to different distances. Particularly in the PoS-based distances, one can observe all of the 21st century Low Saxon dialects shifting towards the modern majority languages.

We present a new comprehensive dataset for the unstandardised West-Germanic language Low Saxon covering the last two centuries, the majority of modern dialects and various genres, which will be made openly available in connection with the final version of this paper. Since so far no such comprehensive dataset of contemporary Low Saxon exists, this provides a great contribution to NLP research on this language. We also test the use of this dataset for dialect classification by training a few baseline models comparing statistical and neural approaches. The performance of these models shows that in spite of an imbalance in the amount of data per dialect, enough features can be learned for a relatively high classification accuracy.