Words and their nine categories

Parts of speech is the traditional term use for the categorizing words according to their functions in English language's sentences and is broadly nine at present, which are:

1. Nouns
2. Pronouns
3. Verbs
4. Adjectives
5. Adverbs
6. Prepositions
7. Conjunctions
8. Interjections
9. Articles

Each one of the above has its own significance and pivotal role in the language without which the meanings of the statement(s) would be incomplete. It can be well understood by reading the following poem:

THE PARTS OF SPEECH

Every name is called a NOUN,
As field and fountain, street and town

In place of noun the PRONOUN stands
As he and she can clap their hands

The ADJECTIVE describes a thing,
As magic wand and bridal ring

The VERB means action, something done -
To read, to write, to jump, to run

How things are done, the ADVERBS tell,
As quickly, slowly, badly, well

The PREPOSITION shows relation,
As in the street, or at the station

CONJUNCTIONS join, in many ways,
Sentences, words, or phrase and phrase

The INTERJECTION cries out, 'Hark!
I need an exclamation mark!'

Through Poetry, we learn how each
of these make up THE PARTS OF SPEECH .

(Ref. unknown)