Abstract: A method is disclosed of translating an input sentence in a source language to an output sentence in a target language using a store comprising a plurality of example sentences in the source language each paired with its translation in the target language. A base example sentence is chosen from the store based on a comparison of the input sentence with each of a plurality of example sentences from the store, and its paired translation is used as a translation basis (S2). A portion of the input sentence differing from a corresponding portion of the base example sentence is identified (S3), these portions being designated input and base example unmatched portions respectively. A portion of the translation basis aligned with the base example unmatched portion is located (S4). The input unmatched portion is used to select a set of subsidiary example sentences from the store (S5).