When including something that a character would have written by hand like letters or journal entries is it acceptable to see spelling/grammar mistakes or words crossed out like you would when writing by hand. Or is this just messy and distracting? I have a section of hand written text from a character that struggles with spelling. Is it better just to write some of the words were crossed out as he struggled to find the correct word/spelling? I have only ever see letters written with correct spelling/grammar, but obviously not everyone is good at spelling. Any thoughts?
I think it's perfectly fine, especially when it's a personal letter or journal (for more formal letters, I would really hope there aren't any mistakes) -Crossing words out, is a great way to convey frustration and when there is a struggle to properly word something. -No one has perfect spelling, sometimes when we're unfamiliar with words, we spell them how they sound (which may be incorrect) -And grammar is an easy thing to mess up. There's nothing wrong for a personal hand written letter or journal, to have crossed out words, and having poor spelling and grammar!
Other than grammar mistakes, I think that this would be unnecessarily distracting. Obviously the reader isn't holding the letter in their hands; drawing their attention to the fact that the letter was of course transcribed into the book, but was for some reason transcribed badly, would disrupt suspension of disbelief. If it's absolutely essential for making some point (as in, for example, Flowers for Algernon), spelling mistakes could be used, but...I just don't think it's a good idea.
If the SPAG mistakes serve a story purpose and are consistent with the character of the letter writer (not the author of the book!) then they are fine. In fact, this kind of thing is common enough. I wouldn't go overboard transcribing all the crossouts or other visuals though, unless you are giving us a photocopy of the actual letter itself, which I have also seen done. As @ChickenFreak pointed out, you don't want to disrupt the suspension of belief and yank us out of the story to figure out the letter. This can happen if the letter is so incoherent that we struggle to make sense of it—unless the character READING the letter is also unable to make sense of it as well. If that's the case, the narrator character should make this clear ASAP. Just as an example, I've seen fictional letters written by dyslexic characters, who consistently mix up 'd' and 'b.' This works, as long as it's done with purpose. It's almost a character tag. Ditto a character whose spelling is atrocious. It doesn't make sense to correct their spelling in a letter they've written, if bad spelling is part of their character. There is no absolute rule to follow. Just write the way you think the character would write, and then test the result with betas.
