14. A method as claimed in claim 13, characterized in that each target hypothesis comprises a series of target words selected from a vocabulary comprising words in the second language and a null word representing the absence of a word.
14. A method as claimed in claim 13, characterized in that each target hypothesis comprises a series of target words selected from a vocabulary comprising words in the second language and a null word representing the absence of a word. 18. A method as claimed in claim 14, characterized in that: the context of the target word in the target hypothesis which is connected to a source word is contained in at least one of two or more context classes; and the estimated conditional probability of occurrence of the source word, given the target word in the target hypothesis which is connected to the source word and given the context of the target word which is connected to the source word, comprises at least one function having a value dependent on the class containing the context of the target word which is connected to the source word.