Exam markers have raised concerns about widespread problems with illegible handwriting and poor spelling and grammar in last year's WA Year 12 English exam.
A report on the stage-three English exam said "general areas of concern" included written expression and handwriting.
"Candidates should remember that they are writing for a specific audience in the markers and that illegible writing is off-putting," it said.
"Markers expect a few spelling and grammatical errors, even from capable candidates, given the examination context, but there is a widespread problem with the spelling of some words and the use of the apostrophe."
Examination reports were released this week on the School Curriculum and Standards Authority intranet, which is accessible only to teachers. Students sat the exam in November.
English Teachers Association president Wendy Cody said the markers' comments accurately reflected most teachers' experiences.
"In my opinion the handwriting has been worsening over the years," she said.
The deterioration in writing skills could be linked to an increase in students' use of computers to complete most assignments and other schoolwork.
"That makes sense to me but I haven't got any evidence to that effect," she said.
Ms Cody said illegible writing would slow down markers because they would have to take more time to decipher it.
She said students had struggled with apostrophe use for many years, often inserting them where they did not belong, despite English teachers' best efforts.
"That's always been the same," she said.
Markers of the stage-three geography exam also commented on students' poor literacy skills and a lack of depth in longer written answers.
"The overall standard of the candidate responses in some areas was of concern," the geography report said.
Mathematics 3A/B markers said: "Basic arithmetic and algebraic errors were again quite common."
The State Government recently announced that Year 10 students would have to pass a literacy and numeracy test before they were able to graduate from high school because of concerns that many were poorly prepared for employment or further education.