q element produces incorrect quotation marks when language changes

This issue is common across all languages that use the q element.

When a Chinese page contains a quotation in another language, the quotation marks used around that quotation (and inside it for embedded quotes) should be the Chinese ones – not those of the language of the quotation.

Currently, if the language of the quotation is declared on the q tag in HTML using the lang attribute, browsers instead set the quotation marks based on the language of the quote.

For example, if English text is quoted in a Chinese sentence surrounded by just <q>, the quotation marks will be correct:

第一 「second 『third』」

However, if lang="en" is added to the q tag, the result becomes:

第一 “second ‘third’”

Here is a test. There are also tests and results in the i18n test suite.

For more details, see this GitHub issue, which is being used to track this gap.

Start with the linked exploratory test and the i18n test suite results for q-element nesting, then read the referenced w3c/eurlreq issue for the tracked gap. Compare the two language scenarios and determine what requirement or browser behavior needs to be clarified; done means the expected quotation-mark behavior is documented unambiguously.