10. Grammatical metaphor๏
Grammatical metaphor is when a meaning is expressed using an unexpected or non-typical grammatical form. It is a key idea in Systemic Functional Linguistics (SFL) and is used heavily in scientific and academic writing.
In everyday (congruent) language:
Processes are expressed as verbs
Participants are expressed as nouns
Qualities are expressed as adjectives
Circumstances are expressed as adverbs or prepositional phrases
A grammatical metaphor occurs when these meanings are expressed in different grammatical classes.
10.1. The most common type: Ideational๏
The most frequent grammatical metaphor in science is nominalisation: turning a process (verb) into a thing (noun).
This shift allows writers to:
pack more meaning into fewer words
create dense, technical sentences
treat processes as things that can be measured, compared, or explained
10.2. Other common metaphor types๏
1. Processes โ Things (Nominalisation)
Congruent: Rocks melt.
Metaphorical: The melting of rocks โฆ
2. Qualities โ Things
Congruent: The rock is strong.
Metaphorical: The strength of the rock โฆ
3. Clauses โ Noun groups
Congruent: When plates collide, mountains form.
Metaphorical: The collision of plates forms mountains.
4. Circumstances โ Participants
Congruent: Water evaporates in the sun.
Metaphorical: Solar evaporation occurs โฆ
10.3. Why science uses it๏
Scientific writing relies on grammatical metaphor because it:
creates technical vocabulary
allows abstract reasoning
builds compact, information-dense explanations
removes unnecessary human actors
makes processes sound objective and stable
10.4. Before and after example๏
Everyday (congruent)
Scientific (metaphorical)