This item contains annotations that were made as part of the PhD project “ Morphological reduplication in Sign Language of the Netherlands: A typological and theoretical perspective ”. The topic of this specific study is plural reduplication in Sign Language of the Netherlands (NGT). The annotations were made for two types of video data: a corpus data set and an elicited data set. The methods are explained more elaborately in Van Boven ( 2020 , 2021 ). The Excel file ‘plural reduplication – annotations’ contains the annotations made for both data sets. The PDF file 'README - plural reduplication - annotations explained' contains a guide through the Excel file, explaining more about the methods, the data set, and the annotation values. The method used to gather the elicited data is a gap-filling task. A complete translation of the background questions, instructions, and items of the gap-filling task can be found in the PDF file 'gap-filling task - translated'. Edit November 2023: Four additional files were uploaded. The file ‘Plurals in NGT_analysis.Rmd’ contains the statistical analyses of the corpus and elicited data, as reported on in Van Boven ( 2021 ). An HTML-version of this file is also available (‘Plurals-in-NGT_analysis.HTML’). The analyses were conducted in R (R Development Core Team. 2008. R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. http://www.R-project.org). The other two newly uploaded files are the input for the statistical analyses: A .csv version of the Excel file with annotations (‘plurals_reduplication_annotations.csv’), which contains the same annotations as the Excel file, only the file extension is different; And the .csv-file ‘Mouthings_bothannotators’, since a representative sample of the annotations of mouthings was checked by a native signer, as explained in Van Boven ( 2021 ). This file shows the type of mouthing each annotator observed: no mouthing (none); a singular Dutch word (singular); a plural Dutch word (plural); or a ...