Conversion
Conversion is the word-formation process by which a word changes word class without any change in form. It is also called zero derivation, null derivation, or functional shift (Marchand 1969; Plag 2003; Bauer 1983).
A noun like email is used as a verb without phonological or orthographic modification: I'll email you tomorrow. The verb has been derived from the noun, but no overt affix marks the derivation; the change is signalled entirely by syntactic position.
Terminology
The labels are not interchangeable across schools. Marchand (1969) treats the process as zero-derivation, positing a phonologically null derivational morpheme that does the category-changing work parallel to overt suffixes. Bauer (1983) and Plag (2003) prefer conversion, treating it as a relisting of an existing form under a new category without invoking a covert morpheme. Functional shift is a structuralist term emphasising the change in syntactic function. The phenomenon is the same; the analysis differs.
Direction and Productivity
The most productive direction in English is noun-to-verb (Plag 2003).
| Direction | Examples |
|---|---|
| N → V | email, text, Google, friend, unfriend, Skype, host, bookmark, hammer, bottle |
| V → N | a run, a build, a fail, a kill, a read, a hire, a hack |
| Adj → V | to empty (the bin), to dirty, to clean, to dry |
| Adj → N | the rich, the poor, a daily, a regular |
| Prep → V | to up (the price), to down (a drink), to off (slang) |
| Proper N → V | to Google, to Uber, to Photoshop, to Hoover, to Xerox |
English is unusually permissive of conversion partly because its inflectional morphology is lean: most nouns and verbs share a base form unmarked for category, so the same string can slot into either syntactic frame.
Conversion vs Related Processes
Conversion shifts category without changing form; overt derivation uses an affix (modern → modernise). Conversion preserves the source word's segments; backformation removes a perceived affix (editor → edit). Conversion produces a homograph-homophone pair; clipping reduces phonological material (laboratory → lab).
Stress shift sometimes accompanies conversion in noun-verb pairs of Latinate origin: récord (N) vs recórd (V), cónduct (N) vs condúct (V), présent (N) vs presént (V). Some analysts treat the stress shift as a suprasegmental affix, others as a non-affixal alternation accompanying conversion.
Semantic Patterns
Clark and Clark (1979) showed that denominal verbs (N→V) follow predictable semantic patterns, with the verb meaning derivable from the noun's role.
| Noun role | Pattern | Example |
|---|---|---|
| Locatum | put N on/in something | butter the bread, saddle the horse |
| Location | put something in/on N | bottle the wine, shelve the book, garage the car |
| Agent | act as N | to nurse, to captain, to butcher |
| Goal | become N | to widow, to orphan |
| Instrument | use N | to hammer, to brush, to email |
These patterns make new conversions readily interpretable: the first time a hearer encounters to Photoshop, the instrument pattern delivers the meaning.
Productivity in Contemporary English
Conversion is one of the most productive sources of new vocabulary in current English, especially via technology and social media: to text, to tweet, to DM, to friend, to unfriend, to like, to share, to ghost, to Slack, to Zoom. New verbs from proper nouns (to Uber, to Airbnb, to Photoshop) appear continuously; many become generic before any company can prevent it. The V→N direction is also productive in business and tech register: a build, a fail, a hire, an ask, a get.
Teaching Implications
Conversion is high-yield for learners because it multiplies vocabulary at zero cost: a known noun is also potentially a verb. Practical priorities include the noun-verb stress contrast for Latinate pairs (record, contract, conduct, present, conflict, suspect), since misplacement causes intelligibility problems. Conversion also creates listening challenges: the student who knows email as a noun may not parse email me later on first hearing. Activities include category-frame slotting (give a sentence with a blank, ask whether the gap takes a noun or verb) and current-corpus exploration (find recent conversions in news and social media). Conversion is a core feature of natural English usage that textbook grammar often underplays.
References
- Bauer, L. (1983). English Word-Formation. Cambridge: Cambridge University Press.
- Clark, E. V., & Clark, H. H. (1979). When nouns surface as verbs. Language, 55(4), 767–811.
- Marchand, H. (1969). The Categories and Types of Present-Day English Word-Formation (2nd ed.). Munich: Beck.
- Plag, I. (2003). Word-Formation in English. Cambridge: Cambridge University Press.