The acoustic conditions of open-plan office spaces influence wellbeing and productivity perceived by users, but with an inadequate evaluation for workspace, acoustic design in open-plan offices can be a factor that alters user performance. Such is the case in Mexico, where there are no adequate standards to evaluate specific acoustic conditions such as intelligibility. For this reason, this case study aims to evaluate different types of measurement methods for intelligibility. This study was carried out in a university in northern Mexico. The sound measurements were based on the Mexican standard for noise analysis and the ISO 3382- part 3 standards for acoustic measurements for open-plan offices. The psychoacoustic parameters evaluated were Reverberation and Intelligibility, using objective methods determined on S/N and subjective methods based on loss of consonant; where it was analyzed distance between sound source and zones classified by building design characteristics. The results indicated in which points the intelligibility effects increased, observing that Reverberation remained stable in this office, and that the subjective methods presented greater size of the measured sound effect than the objective methods. This finding establishes that subjective methods conformed to Lognormal behavior, which is applicable to other linguistic elements describing speech behavior.