Why some nouns are masculine even though they end with -a?
Have you ever thought why there are some masculine nouns that have -a at the end? They are really confusing because usually nouns that end with -a end up being feminine nouns, but some of them are just masculine.
Actually, the reason behind it is hidden in the Latin language. These three words are problema, idioma, systema in nominative case in Latin, and interestingly they are all neuter nouns that Spanish does not have anymore. When all the neuter nouns are dropped, almost all the neuter nouns in Latin became masculine nouns although some of them end with -a in Spanish and other romance languages that did not retain the neuter noun gender. And, that is how they became masculine nouns with -a ending.
Also, it was amazingly consistent that neuter nouns became masculine nouns in Romance languages, the comparison between Italian, Portuguese, French, Spanish, Catalan, and *Romanian is shown below. (*Romanian still has neuter nouns, thus their noun gender did not change.)
There is an interesting gender difference of 2 Spanish words that came from its singular and plural form of the same word in Latin. A masculine Spanish word animal came from a neuter Latin word animal but there is one different Spanish noun alimaña (vermin) that derived from its plural form animālia (animals: neuter plural), and the word alimaña is actually a feminine noun. So, it is very interesting that a neuter Latin word came from its plural form became feminine and its singular form ended up with masculine gender.
|animal (neuter singular)||el animal|
|animālia (neuter plural)||la alimaña|