To talk on and on in a way that wears the listener out — loud, fast, endless, and not worth listening to. It is the sound as much as the words: someone yammering is noise you wish would stop. You will meet it as a verb, usually with "on" or "away" or "about": he yammered on about his car; they were yammering away in the next room. It can also be a noun for that noise — the yammer of the crowd, the yammer of a radio nobody is listening to. It is informal, faintly comic, and always unkind about the talker: nobody yammers in a way you enjoy. It is not a strong insult, though, more the word of a tired person than an angry one, and it is more common in American and British journalism than in everyday Taiwanese-classroom English. Two extra things. It gets used for machines and animals too — dogs yammer, engines yammer, a phone yammers at you — anything making a continuous complaining racket. And there is an older, gentler meaning, now mostly gone from ordinary speech but alive in old books and in dialect: to whine, wail or complain in distress. That is in fact where the word started, and you can still hear the whining edge inside the modern "talk too much" meaning.

碎碎念、講個不停（吵到別人）；也可指持續的嘈雜聲。跟中文「碎念」很像，但 yammer 更強調音量和吵。