Concept:Productive vocabulary refers to the words we actively use when we speak or write, as opposed to words we only understand when listening or reading.
Explanation:Vocabulary is divided into two types: productive (active) and receptive (passive).
Productive vocabulary consists of words we know well and can use confidently and correctly in our own speech and writing.
These words are regularly recalled and used in different contexts.
In contrast, receptive vocabulary includes words we recognize and understand when we hear or read them, but do not use actively.
Our productive vocabulary is smaller than our receptive vocabulary.
Therefore, the correct definition matches the option that says "words which we use when we speak or write."
Answer:D. words which we use when we speak or write.