Constance and variability. Using PoS-grams to find phraseologies in the language of newspapers

This paper describes the use of a corpus-driven methodology, the retrieval of part-of-speech-grams (PoS-grams), which is extremely effective for the discovery of phraseologies that might otherwise remain hidden. The PoS-gram is a string of part-of-speech categories (Stubbs 2007: 91), the tokens of which are strings of words that have been annotated with these PoS tags. A list of PoS-grams retrieved from a sample corpus can be compared with that from a reference corpus. Statistically significant items are further analysed to identify recurrent patterns and potential phraseologies. The utility of PoS-grams will be illustrated by way of analysis of a one million token corpus composed of texts from ten sections of The Guardian, the Sassari Newspaper Article Corpus (SNAC).