• Spanish quickly decided to stick with pluma, the meaning of which was extended to include the concept of a writing utensil, and practically discarded penna. This is still the case in several Spanish-speaking countries, especially Mexico and Central America - but it's not the only word used for pen.

• Old French used penne and plume as synonyms, later broadening the meaning to the writing instrument. Although "penne" died off in French, it had already passed the word "pen" down to English. Although "plume" is no longer used for pen in modern French (today it's un stylo), it is still fossilized in some expressions like nom de plume (pen name), prendre la plume (to begin writing), avoir une belle plume (to have great writing style or nice handwriting), among others.

As many of you know, "pluma" for pen may not work in many Spanish-speaking countries. Other words used in Latin America are bolígrafo (widely used), lapicero (Spain, Puerto Rico, Argentina, Colombia, Mexico), lapicera and birome (Argentina, Uruguay), esfero (Colombia, Ecuador), lápiz tinta (Chile, Perú) or plumín (Dominican Republic). 

For the sake of comparison with pen(na) and pluma, the word for pen in Portuguese is caneta. The root for caneta is cana, which translates as cane or reed in English. It refers to the hollow jointed stem of a tall grass, especially bamboo or sugar cane, or the stem of a slender palm. The ending -eta is a diminutive, so it literally translates as "cañita" into Spanish. Portuguese went with "pena" for feather, just like in Old French. Pen is penna in Italian, and calamus in Latin, meaning reed. Go figure!