The Art of Language Invention

The dative case is one of the more common cases you’ll find in the world’s languages. Outside of the core alignment cases, the dative is most likely to be the third or fourth case found in a language

in an ergative-absolutive language, the subject of an intransitive verb (in the first and third sentence, the one who experiences sleep) and the object of a transitive verb (the one who experiences a hug) are marked with the same case.

As with sex-based gender systems, phonological similarity will tend to trump semantics in many cases. For example, in Dothraki, all words that end with a collective suffix are treated as animate, such as hoyalasar “music,” ikhisir “ash,” and vovosor “weaponry.”

Even more, though, in the first sentence, the form los, the -o in libros, and the final -o in rojos tell you the subject is masculine. In the second sentence, the form las, the final -a in tarjetas, and the -a in rojas all tell you the subject is feminine. So if you’re listening to someone say either of these sentences in a noisy environment, the redundancy built into the language will give you multiple opportunities to decode the meaning of the sentence—opportunities you don’t have with English.
Though redundancy can be annoying, in language, it makes the message stronger

Having explicated all these systems, there are always certain instances where number marking appears to have trouble appearing. It will vary from language to language and lexeme to lexeme, but there are three categories you’ll want to pay attention to: animacy, definiteness, and mass nouns versus count nouns

Singulative: For languages that routinely mark groups of things or masses, the singulative refers to one of a group of items or a substance whose most basic form is plural or masslike. In Arabic, a word like refers to trees in general as a mass; by adding a feminine suffix, you get , which refers to a single tree. A rough English analogue might be rice, which is simpler than grain ofrice

Paucal number refers to a few of some item, but not to a specific number

all languages have some strategy for indicating (or not indicating, as the case may be) three core grammatical categories (though there are others): number, gender, and case.

Kēli is the word for “cat” above (and, yes, the name of my cat is Keli. I can do that because I’m theconlanger [that sound you just heard was the mic dropping])

Suppletion: Suppletion is when two forms that should be related are not related at all. A great example from English is good and better.