1. A computer implemented method of identifying parallel bilingual corpora from one or more larger corpora accessible over a network using a computer with a processor, comprising: accessing a given website; identifying specific trigger words in text of hyperlinks on pages of the given website that link to other pages; selecting a first subset of data in a first language and a second subset of data in a second language from the other pages linked to by the hyperlinks that have the specific trigger words; verifying sufficient parallelism between the first and second subsets of the data based on a plurality of features of the first and second subsets of data, the features being indicative of whether the second subset of data is a translation of the first subset of data; if the first and second subsets of data are sufficiently parallel, obtaining, with the processor, a first tree structure corresponding to the first subset of data and a second tree structure corresponding to the second subset of data, each tree structure having hierarchically and sequentially arranged nodes comprising hyperlink tags and text nodes representing hyperlinks and text in the corresponding subset of data; aligning, with the processor, the tree structures corresponding to each of the subsets of data according to a hierarchically and sequentially invariant alignment such that when a first node in the first tree structure is aligned with a second node in the second tree structure, then nodes that descend from the second node in the second tree structure are either deleted or aligned with nodes that descend from the first node in the first tree structure and nodes that descend from the first node in the first tree structure are either deleted or aligned with nodes that descend from the second node in the second tree structure; identifying parallel textual segments of the subsets of data based on the alignment of the tree structures; and outputting an indication of the parallel textual segments.