One candidate used the mobile telephone text language in a question requiring candidates to write a letter to a friend.
More than six million provisional GCSE results will be issued next week. Another rise in pass rates, continuing a 20-year upward trend, will feed grade-inflation claims. Last year the number of pupils achieving five good passes rose by nearly 1 percentage point - hitting the Government's 50 per cent target a year early.
Writing in today's TES, senior English examiner Anne Barnes said standards were difficult to define but the process to ensure consistency and fairness was rigorous.
"The candidate who wrote entirely in text message language was very unusual. The script raised difficult questions about how it could be marked and perhaps pointed rather alarmingly to the future," she said.
"The thought and quality of the answer has to be balanced against the fact that it is not standard English when it should be."
Commenting on the standards debate, she said spelling errors in GCSE scripts, seized on as evidence of falling standards, were no better or worse than in previous years.
"Students were able to spell quite complex words because they had trained themselves but misspelt words like 'there' or 'writing'. Some words have effectively changed their spelling. 'Seperate' is now so common that it has almost become an official alternative for 'separate'."
New words and phrases appear each year but Ms Barnes questioned whether these "fashionable errors" were worse than the old ones. In this summer's exams, scripts contained words like "gonna" and "alot". Soap opera phrases also made an appearance, such as, "I will always be there for you" or, " I was well bored".
In general, pupils were writing more structured essays because they were more skilful in exam techniques, Mrs Barnes said.
Francis Burns, another examiner, who marked English GCSE coursework this year, said although the same old mistakes were made, pupils wrote with more insight than 20 years ago. But fears have been expressed that the texting phenomenon could undermine children's grammar.
Dr Ken Lodge, a lecturer at East Anglia University, said: "The quantity of communication is increasing but the quality is rapidly decreasing. There are problems with university students struggling with English."
Poor spelling and punctuation in exams has a long history. Examiners'
reports from the 1800s complain about students' mistakes.
The new trends come as the standards debate rages after the 20th consecutive rise in A-level pass rates. Ministers defended the increase as the well-deserved reward for two years' hard work. But traditionalists point to grade inflation and criticise the modular AS which allows pupils to resit exams and improve grades.
The A-level pass rate rose by 4.5 per cent, to 94.3 per cent, nearly seven times the increase last year. Entry numbers fell but there was a huge 25 per cent rise in the take-up of AS-levels, which are easier than the A2 course.
A-level results, 6 and 7 Platform, 11 Leader, 12