For changing children's dialect-

•  Teesside primary has asked parents to correct children's local accents and grammar.
• Ongar Academy in Essex launched a project to discourage students from using words like ain’t, geezer, whatever, like, and literally.
•  asking parents to “correct” children at home

Against changing children's dialect-

• Banning words is not a sound educational strategy. As Michael Rosen points out, schools have been trying this for more than 100 years to no avail.
• Research shows that gradual transition towards standard English works better
• Young people can be taught formal English, and understand its great cultural utility, without being led to believe there’s something inferior or shameful about other varieties.- makes them engage within their education encouraging interaction

http://www.theguardian.com/commentisfree/2016/may/03/dialiects-slang-children-language-english