You can teach the piano to children from age 3 onwards using the Dogs and Birds method.
It is not necessary to know the alphabet.
Animals symbolize the notes: Dog for D, Bird for B, and Cat for C etc.
I would, without hesitation, recommend "Dogs and Birds" as a most wonderful introduction for our youngest children in the commencement of their musical journey at the piano. Emily Jeffrey – Royal College of Music, Purcell School, and Royal Holloway University of London
What People Say About the Dogs and Birds Piano Method - See some video testimonials here.
The next Two Day Dogs and Birds Windsor Workshop for Teachers will be held on 2nd and 3rd June 2017. Early booking is recommended since the workshop is limited to around 20 participants. The Early Bird Deadline is 2nd May. Download an application form here.