From a historical linguistic perspective, is it true that in the oldest languages, adjectives are a subclass of verbs and verbs are a subclass of nouns?
There are many languages today (so not the oldest languages) that do not have a class of adjectives at all, but code the equivalent of English adjectives all as verbs. That is fairly common. It is less common to conflate all word classes into a single, flexible all-purpose word class, but it does occur. I have not heard anyone claim that verbs are a subclass of nouns in any particular language, and I expect it is just as likely to treat nouns as a subclass of verbs. Certainly, many languages form at least a set of their "nouns" (or names for things) by using participial forms (i.e. verbal constructions). There are undoubtedly many and varied treatments of parts of speech systems out there that you can consult. I recommend Hengeveld and van Lier's "An implicational map of parts of speech", which you can access here: https://pure.uva.nl/ws/files/960348/81922_2010a_hengeveld_vanlier.pdf
Ora Schwarzwald Dear Professor, Thank you very much for your insightful response. As I delve deeper, I am keen to consult authoritative scholarly works to better understand this fascinating aspect of historical linguistics. If it's not too much trouble, could you possibly recommend any seminal papers or authors that discuss the transition from nouns to verbs in history? I am eager to build a more robust understanding with the aid of such resources.Thank you for your time and consideration.
Arok Wolvengrey Dear Professor, Thank you for contributing to the discussion with your valuable insights. I greatly appreciate the resource you shared - Hengeveld and van Lier's "An implicational map of parts of speech".For me, the notion that many languages encode what we consider adjectives in English as verbs is indeed intriguing and adds a fascinating layer to our understanding of linguistic categorization.
In the study of language and grammar, verbs are not considered part of the category of nouns. Verbs and nouns are distinct parts of speech, and they serve different grammatical functions.
Nouns are typically words that represent people, places, things, or ideas. They are often the subject of a sentence and can be used as the object of a verb.
Verbs, on the other hand, are words that describe actions, occurrences, or states. They are the words that typically convey the main action in a sentence and can be used to show what someone or something is doing or the state of being.
In the context of history or any field that deals with language and grammar, verbs and nouns are fundamental and distinct parts of speech, and they are not considered to be part of the same category.
I recommend the article by a colleague, Claire Moyse-Faurie https://books.openedition.org/septentrion/115395
It's in French and focuses on verb-noun opposition in Polynesian languages, but she approaches the subject from a more theoretical point of view and provides further references. Hope it helps!
Here is one example from the history of French, where nouns are historically derived from verbs. The main modal necessity (devoir) and possibility (pouvoir) verbs developed into nouns (le devoir, le pouvoir) used alongside the earlier developed modal verbs.
This is an improvised reply, but in many languages (Indo-European, but also Finnish, which is a Finno-Ugric or Uralian language) nouns usually derive from verbs, and not the reverse. Random examples from English (which is not my specialty): deny > denial, behave > behaviour, sing > singer, speak > speaker, speech, eat > eatery, accuse > accusation, etc. etc. It would be easy to list thousands of examples, where it would be weird to say that it is the noun which has given rise to the verb.
Some verbal forms can serve as nominals in Hebrew and other Semitic languages, e.g., gerundives and some infinitive forms. some verbal forms turned into adverbials, too.