tl;dr
Words do not have inherent parts of speech in English: it all depends on how they’re used.
Bare Words Can Have No “Part of Speech”
There is no way to “remember” the part of speech of a word in isolation, because there is no such thing. Grammatical roles in English are fluid things which are assigned based on how a word happens to be used in any particular utterance.
It’s like asking whether record is a noun or a verb. In speech, stress may help guide you guide you, and in writing, its function in the phrase will tell you the answer for that particular phrase. But there is no guaranteed way to give any definitive answer for a word denuded of its functioning context.
So it makes no sense to try to “remember” which “part of speech” a word “is”, for all of those scare-quoted terms make far too many tacit assumptions of dubious nature. Even part of speech is open to debate. Are their many or few? If there are few, how to express the different subtypes?
For example, try saying something is an adverb. Yes ok, but then you notice that some so-called adverbs act completely differently from others, so much so that you would think there would be distinct names for the disparate roles these two so-called “adverbs” are fulfilling in actual speech.
More trivia follows.
Examples of common words with multiple possible part-of-speech assignments
When you ask about a word’s POS in isolation, it is rare for any one answer to be the full, correct, and sufficient answer. Even words of very strict traditional POS can be readily co-opted into other jobs as need arises.
It’s like asking:
- whether an is an article, a verb, or an archaic conjunction
- whether record is a noun or a verb
- whether awake is a verb or a predicate adjective
- whether cool is a noun, a verb, an adjective, an adverb, or an interjection
- whether mine is a noun, a verb, a possessive pronoun, or an archaic possessive adjective
- whether set is a noun, a verb, or an adjective (or historically, even a whilom conjunction!)
- whether inside is a noun, an adverb, or a preposition
- whether dog is a noun, a verb, or an attributive noun used adjectivally
- whether contra a noun, an adverb, or a preposition
- whether home is a noun, a verb, an adverb, or a locative noun used adverbially
- whether once is a noun, a conjunctive, an adjective, or an adverb
- whether that is a conjunction, a relative pronoun, a demonstrative pronoun, or a demonstrative adjective
- whether adieu is a noun, a verb, and adverb, or an interjection — or some sort of unclassifiable foreign term
- whether minus is a noun, a preposition, an adverb, or and adjective
- whether read is a noun, a verb, or a participial adjective
- whether crap is a noun, a verb, an adjective, or an interjection
- or whether running is a (de)verbal noun, a verb, a participial adjective, or an adverb.
Those questions are all unanswerable when the nude words stand alone. Only when they participate in one or another grammatical construction do they at that point take up the role there assigned to them for that nonce-use. Tomorrow they shall play a different role altogether.
Just how many parts of speech are there?
Even when you start to assign parts of speech (POS) to words in utterances, your working set of possible POS tags is itself open to broad debate. The Art of Grammar “Techne Grammatike” that served the classical community had a mere 8 possible POS tags: nouns, pronouns, verbs, participles, adverbs, prepositions, interjections, and conjunctions. This quickly proved inadequate as articles began to be used in Latin, but it look nearly another millennium still for adjectives to merit their own POS tag.
POS assignment is one of the first steps in syntactic analysis, but cannot be separated from it. You have to grok the syntax before you can assign a word its POS tag. Depending on the language being analysed, and depending on the goal of the analysis, today you will see many, many, many POS tags used “in the wild”. Depending on your purpose, any or even all of these might well apply — and that is to English alone!
Of these, many of the subtypes within the first six categories are subject to morphological inflection under the rules of inflectional morphology that govern that particular classification. You can inflect nouns by number, pronouns by case, demonstrative determiners by number (this, these, that, those), verbs by tense and number and person, and adjectives and adverbs by degree.
nouns
- attributive nouns
- possessive nouns
- count nouns
- deverbal nouns
- mass nouns
- proper nouns
- compound nouns
- vocative nouns (also known as nouns of direct address)
pronouns
- disjunctive pronouns
- dummy pronouns
- impersonal pronouns
- indefinite pronouns
- intensive pronouns
- interrogative pronoun
- personal pronouns
- reciprocal pronouns
- reflexive pronouns
verbs
- auxiliary verbs
- copular or linking verbs
- coverbs
- defective verbs
- finite verbs
- impersonal verbs
- intransitive verbs
- modal verbs
- non-finite verbs
- preverbs
- pro-verbs
- transitive verbs
- bitransitive verbs
determiners
- articles
- interrogative possessive determiners
- demonstrative determiners
- deictic demonstratives
- quantifiers
- multal quantifiers
- paucal quantifiers
- pre-modifiers
- numbers
- cardinal numbers
- ordinal numbers
- measure words
adjectives
- compound adjectives
- demonstrative adjectives
- interrogative particles
- nominalized adjectives
- participial adjectives
- possessive adjectives
- predicative adjectives
- proper adjectives
- absolute superlative
adverbs
- adverbs of manner
- adverbs of place
- adverbs of time
- adverbs of degree
- anomalous/miscellanous/other adverbs
- pro-adverb
- deictic adverbs
adpositions
- circumpositions
- postpositions
- prepositions
conjunctions
- conjunctive adverbs
- coordinating conjunctions
- corellative conjunctions
- subordinating conjunctions
clitics
- proclitics
- enclitics
- endoclitics
- mesoclitics
contractions
- particles
- interjections
- fillers
- foreign words
If that seems like too many to remember, it probably is. For most people. But then again, most people don’t have any need to know a word’s “part of speech” anyway. It makes very little difference, if any, in normal communication. Notice how in this Wikipedia example, words do whatever you need them to do:
In certain circumstances, even words with primarily grammatical functions can be used as verbs or nouns, as in “We must look to the how’s and not just the why’s” or “Miranda was to-ing and fro-ing and not paying attention”.
Those simple examples should definitively put to rest the “part-of-speech question” as being at best meaningless in isolation and at worst misleading and wrong.
It really is of very little to no use at all in almost any real-world situation — and I do not count automated syntactic analysis, natural language processing, and computational linguistics, fascinating topics though they can certainly be in an academic context, as having much to do with real-world situations.