The way language is portrayed in each writers' work is telling not only of the characters' personalities, but of the writer and his/her understanding of how to advantageously use this tool to create a story that captivates the reader.
One of the things I first think about when critics mention language in a manuscript is profanity. Different people have different perspectives on what is appropriate for the different age groups. I write all YA and yes, my manuscript is going to have some profanity in it. Teenagers curse. LOL I, admittedly, had a pretty foul potty mouth when I was in my teenage rebellion years.
Of course, some censorship is required because I don't think a book loaded with F bombs is going to go over well with the parental units. But using the occasional "shit", "hell", and "damn" shouldn't be condemned in my opinion. Especially when it's a part of a certain character's way of articulating themselves. Sometimes "shit" does sound much more believable than "sheesh". LOL
What are your thoughts on language in your particular genre of interest?