Bundles of these features uniquely identify speech segments (phonemes, syllables, words). These segments are part of the lexicon stored in the listener's memory. Its units are activated in the process of lexical access and mapped on the original signal to find out whether they match. If not, another attempt with a different candidate pattern is made. In this iterative fashion, listeners thus reconstruct the articulatory events which were necessary to produce the perceived speech signal. This can be therefore described as analysis-by-synthesis.