Note 13 — I. SOUNDS AND ACCENTS
Reading edition
It was formerly the custom to write the final syllable of the third person plural of the first conjugation ão, thus ámão, amávão, amarão, amaríão. In these cases the accent does not fall on the final ão except in the future amarão. It is now the custom to end these words in am, reserving the ão, for the future which is accented according to the rule.