From Old Texts to Modern Spellings: An Experiment in Automatic Normalisation

We aim to tackle the problem of spelling variations in a corpus of personal Portugese letters from the 16th to the 20th century. We investigated the extent to which the task of normalising Portuguese spelling can be accomplished automatically. We adapted VARD2 (Baron and Rayson, 2008), a statistical tool for normalising spelling, for use with the Portuguese language and studied its performance over four different time periods. Our results showed that VARD2 performed best on the older letters and worst on the most modern ones. In an extrinsic evaluation, we measured the usefulness of automatic normalisation for the linguistic task of automatic POS-tagging and showed that automatic normalisation of spelling helps improve the performance of the POS-tagger.