Noise problems, are dealt with by enviromental health department of your local council, you say you have contacted them, and they won't do anything because children are involved, you must keep badgering them to do something, you must insist that they investigate the noise problem, there are clear guide lines on noise levels, keep making complaints to them, if that does not work, then approach your local councillor for help, or even your MP.
If this is affecting your health, go to your doctor, see if your doctor will approach the council on your behalf, if this affecting your health, also go and see a solicitor, many solicitors give an half hour free consultation, to see if a letter can be sent to your neighbours.
I suggest you keep records of all phone calls made to various departments, person you spoke to, time and date, keep copies of all letters, e-mails etc.,
you must badger and annoy the various departments to get this problem sorted, no one will do it for you.
But first try discussing the problems with your neighbours, in a friendly manner, no good going in all guns blazing, I appreciate they do not speak english, so how about trying to find a neighbour or friend that speaks their language and your language who would be prepared to translate for you, failing that, you can always hire a translator.