1. A method, comprising: Obtaining a collection of texts which are not parallel texts; determining sentence portions within the collection of texts, whose meaning is substantially the same, by comparing a plurality of sentence portions within the collection of texts, and determining at least one parameter indicative of a sentence portion in the first document and a sentence portion in the second document, and using said at least one parameter to determine sentence portions which have similar meanings; and using said sentence portions which have similar meanings to create training data for a machine translation system.