1. A method comprising: receiving, at one or more computers, a first collection of n-grams of a first natural language and a second collection of n-grams of a second natural language, the first and second collections of n grams being associated with one or more probabilities; using, at the one or more computers, the first and second collections of n-grams and the associated probabilities to generate a plurality of randomized ranked collections of n-grams for each of the first natural language and the second natural language, each ranked collection of n-grams of the plurality of randomized ranked collection of n-grams having an ordering of n-grams according to a rarity of the n grams in the respective first collection and the second collection of n-grams; using, at the one or more computers, each of the plurality of randomized ranked collections of n-grams to determine a plurality of signatures, each signature corresponding to a text of a collection of texts; and using, at the one or more computers, the plurality of signatures to identify candidate text pairs within the collection of texts, the collection of texts including a plurality of texts in the first natural language and a plurality of texts in the second natural language.