This N1 pattern conveys a sense of not knowing or being unsure about something, often with a feeling of worry, skepticism, or irony. It is similar to 'I wonder' but has a more literary, introspective flavor. It is commonly used in written language, such as novels, essays, or formal speeches, and less in casual conversation. When used in speech, it gives an old-fashioned or dramatic effect.

のやら is the most general form and can follow verbs, adjectives, and nouns (with な). ものやら is used when the uncertainty is about a thing, event, or outcome, often with a sense of being unable to even imagine. ことやら is similar but emphasizes the situation or fact. In practice, the differences are subtle, and のやら is the safest choice for most situations.

The pattern often appears in the structure AやらBやら, but here it stands alone as a sentence-ending or clause-ending particle. It is often used with question words like どこ, なに, いつ, だれ to mean 'where/what/when/who on earth...'. It can also be used without a question word to express general bewilderment.