With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: In China and Taiwan, diglossia has been a common feature. For example, in addition to Standard Chinese, a resident of Shanghai might speak Shanghainese; and, if they grew up elsewhere, then they are also likely to be fluent in the particular dialect of that local area. A native of Guangzhou may speak both Cantonese and Standard Chinese. In addition to Mandarin, most Taiwanese also speak Minnan, Hakka, or an Austronesian language. A Taiwanese may commonly mix pronunciations, phrases, and words from Mandarin and other Taiwanese languages, and this mixture is often used in informal speech, but it is even more common to use Mandarin in formal speaking.
text_B: If a Taiwanese ambassador was giving a rigid, formal speech to the UN, in which she spoke almost entirely in a Taiwanese dialect, using Mandarin only when no reasonable substitute for a word or phrase was available, could this be construed as being somewhat combative, given the usual Taiwanese method of speaking formally?
YES.