In the AMPER project framework the study of several types of corpora is considered. Among them, the so-called fix corpus is especially relevant because word-stress structure, pitch accents, modality and segments can be easily controlled. Since we want to ensure that the corpora registered sound extremely natural, we have carried out this research comparing the utterances obtained from a control informant, who read in the conventional alphabetical way, with those obtained from a pictogramic reading that could be considered as more natural. The result indicate, certainly, that there is a coincidence between both types of rading. This kind of corpus is necessary because they facilitate the comparison of the same structures in different geolinguistic varieties.