If anyone is interested in learning Makaton, the first place to start would be youtube. There are loads of videos on there teaching the signs. The Makaton charity website is also a good source of information.
I work in a special needs school, and we all use it all the time, whatever the childs need/ability. We also use PECS extensively, particularly for autistic/non-verbal children.
We are lucky in that we have a wonderful lady who passes on her knowledge of Makaton by running courses for staff and families at least once a year, free of charge, but I can understand (sort of) that if the course is independent of an SEN school, then there would be a charge for it.
Another way to learn it, which really appeals to little ones especially, is SingingHandsUK. Two lovely ladies, Suzanne and Tracy, who sing childrens songs/rhymes using Makaton. They can also be found on youtube.
If you are able, I would recommend to anyone that they learn the basics of Makaton. It is a simpler version of BSL, but still recognisable to anyone who is only BSL trained. And it comes in handy with any child I've found, special needs or no, particularly if you want to emphasise something. My 3yr old DGS certainly reacts more promptly if I reinforce what I am saying with my hands, whether positive or negative!
I used to practice my Makaton with a profoundly deaf friend, although some of the signs he taught me from BSL I certainly couldn't use in school, the naughty chap! Handy to know if someone annoys me, and I want to react without seeming to lose my temper though
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Enjoy your course nina, it's a shame you have to pay, but it will be SO worth it to be able to communicate more effectively with your DGC. 