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..
Yahoo (or someone pretending to be Yahoo) has been asking me, twice in the last few days, to "renew" my log-in details, including username and password, otherwise I might be "disconnected" Some of the messages contain faulty English. Now I never give these details unless absolutely sure of the sender. Does anyone know if this is a genuine request, or could you find out with the real Yahoo if it is? Thanks.