Certain laws of transformation are found to operate in the Romance languages. One of these is, that Latin or Italian words beginning with f appear in Spanish with an h initial. Thus ‘filius,’ ‘figlio’ (a son), is, in Spanish, ‘hijo.’ By the same law the Latin ‘femina’ (a woman) becomes, in Spanish ‘hembra,’ ‘formosus’ (beautiful) is ‘hermoso,’ ‘Fabulari,’ Italian ‘favellare’ (to talk) is, in Spanish, ‘hablar.’ ‘Faba’ (a bean) is, in Spanish, ‘haba.’ The Latin ‘Facere,’ Italian ‘fare’ (to do), becomes ‘hacer,’ filum (thread) is ‘hilo,’ and folium (a leaf) ‘hoja,’ &c.
The Spanish word ‘hidalgo’ (a nobleman) is a contraction of ‘hijo d’algo’ (filius alicujus), literally ‘the son of somebody,’ i.e., of importance.
It may also be observed that the combination ct in Latin is found in Italian tt (or t), and in Spanish ch. This may be seen in the following cases:—
| Lat. | Ital. | Span. |
| Factus | fatto | hecho |
| Sanctus | santo | sancho |
| Dictus | detto | dicho |
| Directus | diritto | derecho |
Again, pl in Latin becomes pi in Italian and ll in Spanish, as in the following:—
| Lat. | Ital. | Span. |
| Planus | piano | llano |
| Plenus | pieno | lleno |
| Pluvia | piova | lluvia |
| Planctus | pianto | llanto |
Affinities also exist between certain letters of the alphabet; and this relationship may be often seen in words transferred from one language to another. For example, the labials, or lip-letters, are frequently interchanged. Many English words beginning with an F are derived from Latin (or French) words having a P initial. This is exemplified in the following list:—
| Latin. | French. | German. | English. |
| Pater | père | Vater | father |
| Piscis | poisson | Fisch | fish |
| Pes-pedis | pied | Fuss | foot |
| Paucus | peu | — | few |
| Per | pour | für | for |
| Pellis | peau | Fell | fell |
| Pullus | poule | Vogel | fowl |
| Pugnus | poignée | Faust | fist, &c. |