I would (immediately) say it's not real, if the English is "faulty" as you say. I'm also taking into consideration what was posted yesterday in the News thread. You might benefit from reading it.
Yahoo Mail Accounts Have Been Getting Hacked for Months
More importantly, I would suggest reading "Received an unsolicited email asking for password or other personal information" and "Suspicious Activity" from Yahoo Account Help. They should help determine whether they are real or not.
I would recommend changing your password, even if you come to find it is legitimate. You have nothing to lose by making the change.
Best of luck..