The verb turn is a so called factitive verb in certain its meanings and grammatical patterns.
For example, look at these sentences:
- The heat turned the leaves brown.
- The high atmospheric pressure turned the weather cold.
- The university turned him educated.
The grammar behind the patterns having factitive verbs
In accordance with the morphological characteristic of the so called factitive verbs developed by the science of grammar, the factitive verbs can have both direct objects and object complements.Object complements are adjectives, nouns, pronouns or phrases that follow direct objects in order to indicate what the new state of the direct object is. In other words, the object complement reveals what the direct object has become.
The words the leaves, the weather, him are the direct objects in the examples above.
The words brown, cold, educated are the object complements in the examples above.
Therefore, the verb turn is a factitive verb here, which functions as a transitive verb. The majority of factitive verbs, for example, several of them are elect, appoint, make, choose, deem, assign, name, select, judge, and designate , are usually transitive that is in consistence with the description of their morphological characteristics.
It is difficult to imagine how the verbs listed would retain their own morphological characteristic if they were used intransitively.
- He made student. (ungrammatical)
- He assigned supervisor. (ungrammatical)
- She elected MP. (ungrammatical)
The verb turn is one of the exceptions among the factitive verbs
But, the verb turn retains its characteristics as a factitive verb, even if it is used as an intransitive one, as in the question that belongs to the OP. For example,
- My brother has turned writer.
- His senior relatives, some of whom are in arts themselves, have turned my brother writer. I am proud of him.
So, the verb turn bears some elements of the so called ergativity in own morphological characteristic. As the verb open, for example. Though, the verb turn is not an ergative one in a strict sense of this morphological (grammatical) term.
The verb turn often is called a copular (linking) verb in many dictionaries and grammars. It is not a correct description, in some strict sense. The verb bears very complex morphological characteristic, several elements of which I tried to indicate briefly here above. Such definition in dictionaries just tries to explain its syntax in simple words for learners.
This question of how to understand the grammar and semantics behind such factitive verbs is applied to the problems of the grammar and semantics behind the patterns of imperative constructions as well, for example. We may study two sentences from the modern English-language newspapers. The first is published with US editorial staff, the second - with Malaysian staff.
"Don’t be traitor and lose your seat.", The Navajo times, 12 December, 2017.
"Do not be a traitor to your motherland.", The Star, 23 February, 2015.
As it will be mentioned further, the verb be is one of the verbs that can bear the features of linking and factitive verbs in some patterns. For example, we never say It is a Wednesday today. Instead, we usually say It is Wednesday today in the conversational and written speech. But, such an example of a written speech as It was a Wednesday when everybody was tired in the middle of a working week is possible and grammatical.
So, after reading above, it seems, you can answer the question put; not in detail really, but, on some sufficient level for the learners interested in such scientific-popular problems.
Any other answers for the learning task (quiz) from the OP are impossible. It is My brother has turned writer only, because of the meaning of the second sentence I am proud of him. The second sentence licenses the complement in the first sentence writer as an abstract noun. The general connotation of the sentence is positive.
For comparison, the general connotation of the sentence My brother has turned a writer could be neutral or negative usually. Such a sentence must be within a certain context that is established unambiguously. Noun writer is a concrete one here. The postmodifying phrase, or clause, is necessary usually in such a sentence. It could determine the general connotation of the whole sentence. For example, My brother has turned a writer, who is working in time off.
Detailed answer to the question in the OP
Taking into account the volume of your question, I repeat it in full and give answers to each sentence of your question.
Looking for a grammatically detailed and reference-based answer that addresses:
- The existing answer seems to suggest "turn + zero article + noun" is a singular linguistic oddity. Is that really the case? Are there any other verbs which when used copulatively take the zero article and a noun?
Answer. I shouldn't call such syntax an oddity. Such patterns are just unusual in everyday speech, but very informative in some styles of writing, and even in certain professional jargons.
We should use the pattern turn+zero article+noun in the sentence.
There are some other verbs that are used in their certain lexical senses, for example, be, grow, go, sound, become that can support factitive sense of certain patterns with them. For example,
He has grown writer.
He has grown wrestler.
He went manager.
The young has grown singer and rapper who moved to the international market so fast after his hit tune "Iron man", which got recognized alongside Burna boy's Anybody among Nigerian beautiful songs by the former president of the United States of America, Barrack Obama. Opera News Official, 2020.
GUPTA: Liz Devine is the supervising producer. Before going Hollywood, she spent 15 years as a criminalist with the L.A. County's Sheriff's Department. CNN.2005.
...the Company didn't have the right to go manager/operator. Decisions and Orders of the National Labor Relations Board, Volume 334 United States. National Labor Relations Board.
- And why "turn"? What's so special about "turn"? Why do we say "He turned traitor." but "He became a traitor."?
Answer. The special characteristics of the verb turn have been described in short above. Yes, it is a special verb having special syntactical and morphological characteristics.
We use the pattern Subject+turn+zero article+noun, as in He turned traitor, to inform a hearer about the state of self-perception that a person that is referred to by the Subject-pronoun has achieved or about resulting condition of something.
In case of turn used as a linking verb we use the pattern Subject+turn+indefinite article+noun just for relating the person that is referred to by the Subject-pronoun to some indefinite set of traitors in the perception of the society.
You can understand after reading the paragraph that these patterns have different senses.
- What part of speech is "writer" in "He turned writer"? Is it an adjectival given its syntactic similarity to "red" in "The sky turned red." Any other examples of nouns functioning in a similar way? Please cite an authoritative source on this. 4. Why do we say "He turned red." "He turned writer." but "His face turned a slight pink color."?
Answer. Writer in such pattern is a noun functioning as a subject complement.
No. It is not an adjective. Complements in the patterns of factitive verbs can be either adjectives, nouns, pronouns or phrases. It is a noun writer in the case.
There are a lot of nouns that can function in the pattern in the similar manner, for example, He turned politician, he turned journalist, he turned TV-presenter and so on.
The pattern tells us about the state of self-perception of a person or resulting condition of something. That is why, His face turned a slight pink colour means in essence His face is a slight pink colour, (not so well composed).
But, the pattern His face turned slight pink means in essence The resulting condition of his skin is that its colour has become slight-pink.
Here are some useful examples to explain how complements may look in the patterns with the factitive verbs:
The populace elected Obama president of the United States.
The committee named Mr. Fuller chairman of the board.
The jury judged the defendant not guilty.
She deemed him person of high quality.
The group designated Marshall leader from then on.
The coach made Messi captain of Barcelona.
The most widely accepted linguistic terminology on this subject can be found here: https://en.m.wikipedia.org/wiki/Resultative
There is no any source on such topic in the open media space. In any case, I haven't met any yet. Similar, but much more strict with its terminology and style of presentation, content is for the specialized editable publications of the paid journals.