The recent history of the Live Samples article illustrates a pattern that I’ve seen any number of times on MDN:
- Native-English-speaking writer (e.g., Sheppy) creates a heading of the form [Question-word] [noun phrase] [verb phrase] (“How the live sample system works”).
- Possibly-not-native-English-speaking contributor (e.g., ajith913) sees the question word, thinks this heading is a question, and adds a question mark to the end of it (“How the live sample system works?”).
- Native-English-speaking contributor (e.g., sideshowbarker) sees the question mark, realizes that the heading is not a well-formed question in English syntax, and adds the “helping verb” does to the heading, making it a syntactically correct question (“How does the live sample system work?”).
I posit that this pattern arises because the form [Question-word] [noun phrase] [verb phrase] is easy for non-native-English-speakers to mis-parse, if they have not internalized all the use cases for when adding do is necessary, or prohibited, in English. In many languages other than English, [Question-word] [noun phrase] [verb phrase] is a valid syntax for a question. In English, it is a short hand for This section describes [question-word] [noun phrase] [verb phrase]. In English, the corresponding question syntax is [Question-word] [do|does|did] [noun phrase] [rest of verb phrase]?.
I propose that we adopt a style guideline:
If a heading starts with a question-word (who, what, where, when, why or how), make sure that it is in the form of a question, and ends with a question mark.
This imposes a slight burden on native-English-speaking writers to avoid an otherwise valid structure, in the interest of easing the cognitive burden on (potentially millions of) non-native-readers.