The correct term for the study of old handwriting is palaeography.
One of the challenges facing family historians is reading and understanding old documents. Handwriting styles have chaged so much over the centuries. Old documents can contain many archaic terms - old monetary terms, unfamiliar date forms - and the whole document in strange writing may appear unrecognisable to the inexperienced eye.
Documents produced since the mid-nineteenth century use words and letter formations similar to those used today. But as you work back in time, the letter styles become increasingly strange, even though they are in English. This is where you need palaeographic skills. Gaining experience in reading older script and then analysing the documents written in those styles are the two skills most needed to interpret the information a record contains. Every family historian should try to gain some palaeography skills to enrich their understanding and interpretation of records.
Between 1500 and 1900 documents were written in a variety of handwriting styles. Not only that, the various styles were often mixed up; in many cases, the styles depended on how the scribe was educated. For most family historians it should be straightforward to decipher documents written after 1750, but everyone will come across some older and difficult forms of writing perhaps as late as the 1850s. It is very much a case of practice makes perfect!
The dominant style of handwriting from the early modern period in England and Wales, was secretary hand. While English was the predominant language, Latin was the official ecclesiastical and legal language until 1733; but Latin phrases lingered in various documents, sometimes until the nineteenth century. Some Catholic registers still use Latin even today. Documents from the Channel Islands will contain French words.