Weird English Plural
You probably know that “media” and “data” are actually plural forms of “medium” and “datum”. Or are you a kind of person who uses “medias” instead of “media”? There are many more plural nouns that do not end with -s or -es, and children, men and women are very famous ones. Also, while these knouns change its forms, but there are nons that do not have plural marker and still means plural like fish, deer or sheep.
1．Medium is singular and media is plural because…
As a reason, these nouns actually came from Latin, and we use these words by using the exact same Latin words. Also, these Latin words mark their plurality by changing the ending rather than just adding -s or -es. Thus, we have Latin plural words without -s or -es in English now.
|Medium (Latin: middle)||Singular||Plural|
|Alumna (Latin: female student)||Singular||Plural|
As you can see, we still use the same words with different meanings from its original Latin.
２．You cannot say *mans or *childs because
Words like “man” and “woman” also have irregular plurals because of an old language, but they are from Old English. As Latin does, Old English also requires the noun declension for all the words except for indeclinable ones.
|Nominative||ċild||ċild, ċildru, ċildra|
|Accusative||ċild||ċild, ċildru, ċildra|
３. Some words “sheep/deer” do not mark plural because…
These nouns are also influenced by good Old English. In Old English, neuter nouns with long syllables do not have endings, which basically means that they do not change its form whether they are plural or singular. So, fundamentally, they became to be those nouns that do not make the plural. However, not all of them stayed that way, and some of them have -s or -es ending in their plural form. Also, more interestingly, some of the words that do not make plural were not even in this neuter noun group. Here are some examples of these 3 types of nouns that retained the rule, those who did not retain the rule, and those who applied the rule needlessly.
In this case, sheep remained the same sheep in plural in Modern English.
Even though thing did not have the ending, but now in Modern English, we mark plural with -s.
Fish does not mark plural even though it used to mark plural in Old English.
Please let a comment if you have any questions.