のやら is a formal and somewhat literary expression often used in writing, particularly in contexts where there’s uncertainty or ambiguity. In conversation, のやら might sound formal, old-fashioned, or poetic. You’d be more likely to hear it in stories, songs, or reflective essays than in casual dialogue. When used in speech, it can have a slightly dramatic or philosophical nuance. For example: 彼がどうしているのやら (I wonder how he’s doing). のやら is often used in set phrases or rhetorical questions, like どうなることやら (what will become of this?) or いつになることやら (who knows when...). In more casual or everyday speech, people would typically use のか or のかな instead: 彼がどうしているのかな。