Meaning: 'Trading' refers to the act of buying, selling, or exchanging goods and services, particularly in a commercial context.

Wrong options:

• connecting: Connecting implies establishing a relationship or link, which does not specifically convey the economic activity relevant to the context of pidgins.
• speaking: Speaking is a general term for verbal communication and lacks the specific commercial connotation needed here.
• talking: Talking is informal and does not capture the economic exchange aspect that 'trading' does.

Correct answer: vocabulary

Explanation: The term 'vocabulary' is appropriate as it refers to the set of words used in a language, which is what one of the language parents contributed to the pidgin. This aligns with the grammatical structure of the sentence, which discusses the components of language formation.

Meaning: 'Vocabulary' means the collection of words and phrases used in a particular language or by a particular group of people.

Wrong options:

• grammar: Grammar refers to the rules governing the structure of sentences, which is not what is being discussed in this context.
• knowledge: Knowledge is a broader term that does not specifically relate to the linguistic components of pidgins.
• verbal: Verbal pertains to words or speech but does not specifically denote the collection of words as 'vocabulary' does.

Correct answer: known

Explanation: The word 'known' is the correct choice as it indicates recognition or identification of pidgins as creoles when they become mother tongues. It fits grammatically and contextually, as it describes the status of pidgins in relation to creoles.

Meaning: 'Known' means recognized or identified, particularly in the context of language classification.

Wrong options:

• regarded: Regarded implies a subjective opinion and does not convey the definitive status of pidgins becoming creoles as effectively as 'known.'
• considered: Considered suggests a thought process but lacks the assertive recognition that 'known' provides in this context.
• recognized: Recognized is similar to 'known' but does not fit as smoothly in the sentence structure.

Correct answer: any depth

Explanation: The phrase 'any depth' is suitable as it indicates the extent of discussion that will not occur in the book. It fits grammatically and contextually, suggesting a lack of thorough exploration of the topics mentioned.

Meaning: 'Any depth' means to any extent or level of detail, indicating that the author will not delve deeply into the subjects of pidgins and creoles.

Wrong options:

• any width: Any width is an incorrect phrase in this context, as it does not convey the idea of depth or thoroughness in discussion.
• further: Further implies continuation but does not specify the level of detail, making it less precise than 'any depth.'
• next time: Next time suggests a future discussion but does not address the current scope of the book, making it irrelevant here.