Being able to write semi-readable written text with technical terminology is a huge skill, and makes such a difference compared to not being able to write it.
I've found that since blogging more, my written language has gotten a lot better, and significantly makes my job easier.
I've worked with a number of brilliant engineers who can't explain themselves as well in written forms, which means commit messages and core pieces of documentation are difficult to understand.
Remember that you're never going to be the only person reading something, so make your content well thought out, re-read it and ask someone else to read through it to check it's OK.