2. The method of claim 1 , further including: using results of the similarity tests to map at least part of the second language phonemes to sets of phonemes of the first language by: assigning respective scores to results of the similarity tests; and mapping one or more of the second language phonemes to a set of mapping phonemes of the first language, the set of mapping phonemes being selected from the candidate mapping phonemes as a function of the scores; and including the first language sets of phonemes resulting from the mapping in a stream of phonemes of the first language representative of the text to produce a resulting stream of phonemes that are used to generate a speech signal.
4. The method of claim 2 a wherein the mapping comprises: defining a threshold value for the results of the similarity tests; and mapping onto the empty set of phonemes of the first language any phoneme of the second language for which any of the scores fails to reach the threshold value.