The answer is... quite a lot.
Makaton was developed for hearing people with learning or communication disabilities, so that those who were non-vocal or had limited vocal abilities would have another way of communication. It uses sign, symbols and speech in the same order as spoken English. It is relatively new, being created in 1991.
Although it borrows some sign from BSL, it is not a language in itself. People who learn Makaton often have family or friends with learning disabilities or work in an environment that supports those with additional needs.
British Sign Language is an officially recognised language used by the D/deaf community and others who use BSL as a tool to communicate. It has a rich and long history and like other modern languages (English, French, German etc) it has a vast vocabulary including it's own slang and regional variations. Although it may be used by those with learning or other additional needs, it is not unique to this community and is easily used to convey complex and multi-faceted ideas. In fact, just like English, (Googling, Lockdown, Twerking all being recent additions to the dictionary...) BSL is evolving all the time with new or amended signs being added to the language every year.
It's important to note that while Makaton follows spoken English structure, the order of BSL is different and follows it's on rules of grammar which is quite different to spoken English.
If you already know Makaton, you may find some of the signs you know are already used in BSL, however knowing Makaton can also make it more confusing to separate the two. Here at Sign Together we teach British Sign Language Levels 1 and 2 and Deaf Awareness workshops to help you be more inclusive of d/Deaf and heard of hearing people.