The Wikipedia article Morphology says:

A further difference is that in word formation, the resultant word may differ from its source word's grammatical category whereas in the process of inflection the word never changes its grammatical category.

I can partly understand this statement and how "dishwasher" is different from both "dish" and "washer", but I couldn't understand how "the word never changes its category":

  • I wash dish. (verb) / He breaks glass.
  • A pile of washed dish (adjective) / some broken glass

"Washed" and "broken" are inflected forms of "wash" and "break", but they can be used as non-verb. This is clearly a different grammatical category.

I'm certainly misunderstanding either "inflection" or "grammatical category". What am I missing?

  • 2
    Washed and broken as used here are not generally considered inflected forms of their respective verbs in English – they are adjectives that happen to be identical (in form) to the past participles of those verbs. In this case, we usually say that the adjective is derived from the participle by zero-derivation (which is exceedingly common in English). Some would also consider participles themselves to be derivations, not inflections, but that’s rather circular to me. Commented Oct 22, 2021 at 15:58
  • 2
    @JanusBahsJacquet I'm under the impression that virtually every single past participle can be used as an adjective (when sensible). Also participles (present and past) are usually thought to be inflections, aren't they?
    – iBug
    Commented Oct 22, 2021 at 17:38
  • 1
    Yes, pretty much. So can the vast majority of nouns. That doesn’t mean there’s no derivation involved. Commented Oct 22, 2021 at 17:38

2 Answers 2


The Wikipedia article means part of speech when it says grammatical category. While the statement is true (with some caveats, participles are counted as inflected, but categorised as verb forms usually, therefore not changing part of speech) for most European languages, both ancient and modern, I am not so sure about other language families, specially the Semitic languages.

Of course, one can define inflection and derivation in a way such that inflection never changes part of speech, but such a definition may be unsatisfactory for other reasons.

The English language has the feature that it can easily change the part of speech of a word without changing the word form itself (To verb a noun and to noun a verb, as a proverb says), this is interpreted as zero derivation in some theories. In English a word form can have different part of speech depending on its usage in a concrete sentence.

  • 6
    I wouldn’t call zero derivation ‘unique’ to English – it’s quite common in lots of isolating languages. Commented Oct 22, 2021 at 17:40
  • @JanusBahsJacquet I removed unique now. Commented Sep 21, 2022 at 21:50

What's happening in your example isn't an inflection but a conversion.

Washed is both an inflected form (Past Participle, Present Indicative, Present Perfect, etc all end with -ed) but it's also a participial adjective. The participial adjective is obtained by a word formation process called conversion:

In linguistics, conversion, also called zero derivation or null derivation, is a kind of word formation involving the creation of a word (of a new word class) from an existing word (of a different word class) without any change in form,1 which is to say, derivation using only zero.

In conversion the word can change category (verb to adjective), the inflection is considered to have already happened when the conversion takes place (the inflectional suffix -ed is not considered a derivational suffix).

In terms of morphemes you could consider the inflection to be:

Wash+ed (Verb)

and the conversion to have a zero morpheme:

Wash+ed+ (Adjective)

So your examples could be written as:

I wash dish. (verb) / He break+s glass.

A pile of wash+ed+ dish (adjective) / some brok+en+ glass

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.