In the few documents that she left, she signs with a mark. But Martha clearly is. And some scholars believe it's really Martha's generation when more and more women learn rudimentary writing. So when we talk about literacy in that period, we're talking about something a little more complex than when we talk about it today. So children were taught often to read the Bible, but not to write.
Writing is an active thing.
And it's really associated with craft, with certain occupations, with the male role as head of the household, as owner of property. And the assumption was girls didn't need that skill. They were taught to sew. We don't know how Martha learned to be a midwife. And I can guess that on the basis of the diary, because the diary describes a world in which each birth was attended by a number of people, neighbors, relatives, friends.