The RASTI-method is a simplified version of the speech transmission in
dex, that has been evaluated in several languages. In this paper, a co
mparative study of the scores of speech intelligibility obtained by th
e traditional speaker-listener tests in the Spanish language and the R
ASTI-method has been carried out in classrooms. The list of monosyllab
ic words used are phonetically balanced and representative of the Span
ish language. The percentage of monosyllables giving a poor and bad RA
STI-index decreased more slowly when the words were pronounced without
a prerecorded voice.