Book 1
4.12
A boy therefore must learn both the peculiarities and the common characteristics of letters and must know how they are related to each other. Nor must he be surprised that scabillum is formed from scamnus or that a double-edged axe should be called bipennis from pinnus, sharp : for I would not have him fall into the same error as those who, supposing this word to be derived from his and pennae, think that it is a metaphor from the wings of birds.
4.13
He must not be content with knowing only those changes introduced by conjugation and prefixes, such as secat secuit, cadit excidit, caedit excīdit, calcat exculcat, to which might be added lotus from lauare and again inlotus with a thousand others. He must learn as well the changes that time has brought about even in nominatives. For just as names like Valesius and Fusius have become Valerius and Furius, so arbos, labos, vapos and even clamos and lases i.e. of lares. were the original forms.
4.14
And this same letter s, which has disappeared from these words, has itself in some cases taken the place of another letter. For our ancestors used to say mertare and pultare. For mersare and pulsare. They also said fordeum and faedi, using f instead of the aspirate as being a kindred letter. For the Greeks unlike us aspirate f like their own phi, as Cicero bears witness in the pro Fundanio, where he laughs at a witness who is unable to pronounce the first letter of that name.
