With dialect, less is more, for sure.
We are a nation of poor readers. The average for the general public is 5th grade level.
I grew up reading Frances Hodgeson Burnett’s thick dialect in THE SECRET GARDEN, but most readers today don’t have patience to decode all those missing letters and apostrophes in strange places. They go rent the movie, which also has very little dialect.
I’ve met people from Northumberland. I wasn’t sure they were speaking English.
Dialect can be very difficult to write well. This is a lesson I learned, reluctantly I’ll admit, in a workshop with Diana Gabaldon. She wrote a book about a group of 17th century Scots, and English OUTLANDER. No dialect is a thick as that of Scotland. Diana said she listened to old Scots ballads sung in English and in Gaelic to absorb the rhythm of the speech. There’s a great deal of difference between the speech of the Scots and the Englishwoman, and among the Scots, depending upon their station in life and educational level. But nobody said, “Hoot mon!” She changed didn’t to didna, and wouldn’t to wouldna, and added some dated terms like “foxed” for drunk. But most of it was in the rhythm of the language.
Because of the sentence construction, English just plain sounded different when the Scots spoke, but their meaning was never obscured by a lot of fancy punctuation.