Sometimes Siri activates itself and starts talking
Siri is the program on an Iphone that you can ask questions or call people by voice activation, if something talks without doing or saying anything then it is said to 'talk by itself'
to activate something means to make it start working or do something
Siriとは、質問に答えたりあるいは音声認識で電話をかけてくれるiPhoneのプログラムです。
何もしていないのに勝手にしゃべり出すことは、'talk by itself'（ひとりでに話す）で表せます。
'activate' は「～を起動する／作動させる」という意味です。
My iPhone starts talking all of a sudden.
私のiPhoneは突然喋り出す。
all of a sudden = 突然、前触れなしに
私のiPhoneも同じような現象が起きて困っています。
I don't know how to fix it!
どうやって直せばいいのか分かりません！
This is weird. Siri sometimes activates itself and start speaking.
*Siri activated itself on its own accord.
On its own accord is used to suggest that something happens by itself without anyone causing it to happen.
For example
"The tree fell of its own accord."
例文
*Siri activated itself on its own accord.
Siriが独りでに起動しました。
On its own accord は、人が操作していないのに、何かが独りでに作動することを表す時に使われます。
例文
"The tree fell of its own accord."
その木は独りでに倒れた。
Sometimes, Siri starts talking by itself.
This really explains to the other person, that Siri would turn on by itself on your phone and start talking. Without you needing to turn her on.
Siri randomly activates by itself.
This is a great way to really show that the act of Siri talking out of nowhere is very random and unnecessary.
E.g
'' Siri just randomly activates on my phone!''
Sometimes, Siri starts talking by itself.（時々、Siriが勝手にしゃべり出す）
これは、携帯のSiriが勝手に起動してしゃべり出すと伝えています。
Siri randomly activates by itself.（Siriが勝手に起動することがある）
これは、Siriが勝手に必要がないのにしゃべり出すことを伝えるすごく良い言い方です。
例：
''Siri just randomly activates on my phone!''（携帯のSiriが勝手に起動してしまう）
On occasion, on my phone, Siri just starts speaking without my prompting
Sometimes, if Siri on your iPhone activates on its own and starts talking, you may express that by using one of the above statements. The first sentence is an exclamation at the time (or shortly after) Siri starts speaking. The second is a general statement which could be made anytime.
インド 
イギリス 
日本 
南アフリカ 
アイルランド 
