Today's theme is complaining and grumbling - a common pastime on the interwebs, especially Twitter.
文句を言う もんくをいう monku o iu - To complain
ぶつぶつ文句を言う ぶつぶつもんくをいう butsubutsu monku o iu To grumble, complain.
Example: あの女はいつもぶつぶつ文句ばっかり言っている あのおんなはいつもぶつぶつもんくばっかりいっている。 Ano onna wa itsumo monku bakkari itteiru
- That woman is always/only (itsumo + bakkari) grumbling and complaining.
You might see some manga characters saying ブツブツ or ぶつぶつ... when they are grumbling under their breath.
On the Japanese version of Twitter, 'tweets' are translated as つぶやき、which means murmur(s) or whisper(s). But maybe calling them ぶつぶつ might be more appropriate ^_^ (Actually I'm not sure why they did not use a more neutral word, or even just ツイッター, but that's another story.
(ぶつぶつ has another meaning - to be bumpy or pimply or spotty. E.g. a if your face if covered with pimples, it's ぶつぶつ。Raw chicken skin is ぶつぶつ。）