Thanks, lordbob.
Well, it seems to perform more or less the same in Word, in Excel or in Iexplorer. Above all, the behaviour is erratic: a umber (say 7) that it understands well may be written in anyone of these formats, unpredictably:
vii (small case always), siete, 7
Or, for dates (1524),
1524, 1500 xxiv (this, quite often), mil 524
It has special trouble with dates: it fails to recognize the common words for months and days of the week much more frequently than other words (and the regional settings in the computer are correctly set for Spain).
There are other smaller malfunctions, like the impossiblity of ordering to type a word with a capital first letter: I can do that only afterwards, by going back to the word and saying 'capital'; but that obviously is a little waste of time.
I find the built-in help specially incomplete for this module of voice recognition; which is a pity, for the recognition itself is fine.
Thanks again for your help.
ACA