Adverbials are an umbrella group of words, phrases, and clauses that function as an adverb in a sentence. And adjectivals are a similar umbrella group that function as an adjective in a sentence. The difference between the two is essentially the same as that between an adverb and an adjective.
1. They play different roles in a sentence
Whereas adverbials answer certain questions (why, when, where, how, etc.) in a sentence to throw light on overall background in a sentence, adjectivals give details about the participants (nouns and pronouns) in a sentence.
This sentence, for example, has adverbials as well as adjectivals. Can you identify them? (Hint: The sentence has three adverbials and one adjectival.)
I went to Subway this afternoon to eat Spicy Italian sandwich for lunch. [Spicy Italian is name of the sandwich.]
The prepositional phrase for lunch describes Spicy Italian sandwich, a noun phrase, and hence is functioning as an adjectival.
The prepositional phrase to Subway answers where and hence is functioning as an adverbial of place.
The noun phrase this afternoon answers when and hence is functioning as an adverbial of time.
The infinitive phrase to eat Spicy Italian sandwich answers with what purpose and hence is functioning as an adverbial of purpose.
2. Adverbials are generally mobile in a sentence; adjectivals aren’t
Mobility in a sentence is another distinguishing feature between the two: We can generally – but not always – move around adverbials in a sentence, but adjectivals have to be close to the nouns they describe. With adverbials moved, here are few variations of the earlier sentence.
This afternoon, I went to Subway to eat Spicy Italian sandwich for lunch.
To eat Spicy Italian sandwich for lunch, I went to Subway this afternoon. [Note that the adjectival for lunch moved with its noun]
So, if you can shift a phrase or clause in a sentence, it’s most likely an adverbial.
Of the two distinguishing features we just saw – role and mobility – role is more reliable as adverbials may not always be mobile.
Since the two distinguishing features apply to any adverbial and adjectival, they can be used to differentiate between an adverbial phrase and an adjectival phrase as well. In fact, the example we considered contained only adverbial phrases and adjectival phrases.
Exercise: adverbial vs. adjectival
Identify adjectivals and adverbials in the following sentences.
1. I work on Hudson Street.
2. My plan to sleep till noon was spoilt by my dog.
3. I can do anything to achieve my goal.
4. Diamond, which is extremely hard and expensive, is produced by intense heat and under great pressure.
5. Opportunities look for you when you are worth finding.
1. I work on Hudson Street. [Adverbial]
It’s a prepositional phrase functioning as an adverbial phrase (of place).
2. My plan to sleep till noon was spoilt by my dog. [Adjectival/Adverbial]
The infinitive phrase to sleep till noon is functioning as an adjectival phrase describing the noun phrase My plan. The infinitive phrase contains the prepositional phrase till noon which is functioning as an adverbial phrase (of duration).
3. I can do anything to achieve my goal. [Adverbial]
It’s an infinitive phrase functioning as an adverbial phrase (of purpose).
4. Diamond, which is extremely hard and expensive, is produced by intense heat and under great pressure. [Adjectival]
It’s a relative clause functioning as an adjectival clause. It is describing the noun Diamond.
5. Opportunities look for you when you are worth finding. [Adverbial]
It’s an adverb clause functioning as an adverbial clause (of time).