Language lessons for project management

Why is people think that the person at the other end of an email should instantly ‘get’ what they have written? Most people in project management teams are trained in technology, but are often poor in commnication, but this is always the fault of the non-techi. Bless. Do-you-still-understand-this-when-you-read-it-again-after-lunch/meeting/dinner/weekend/xmas?!