Today's GCSE candidates are twice as bad at spelling as their O-level counterparts of the 1980s and much more likely to use slang in examination papers - even in scripts awarded top-grade passes.
Spelling mistakes from A-grade candidates in 2004 included "unaturaly" for "unnaturally" and "inevitabely" for "inevitably". Other howlers included "shear" for "sheer" and "boistorous" for "boisterous".
The figures show that, in A to E grade passes, spelling mistakes more than doubled between 1980 and 2004, with 1.9 per cent of words spelt incorrectly in 2004 compared with just 0.9 per cent previously.
For the first time in 2004, girls were just as likely to make spelling mistakes as boys, the researchers from Cambridge Assessment - part of the University of Cambridge Local Examinations Syndicate, reveal.
They are, though, using a richer vocabulary compared with earlier years. Previously, boys had a monopoly on the use of words from higher lexical categories than girls - but now both sexes are equally likely to use them.
The good news is that spelling has improved over the past decade. In the mid-Nineties, mistakes were made in 2.6 per cent of all words. The research project compared scripts from the 1980 O-level exam with GCSE scripts from 1993, 1994 and 2004.
The biggest change is in the use of slang. Among O-level candidates in 1980, it was used in 0.013 per cent of words. In the mid-Nineties, this had risen to 0.05 per cent. However, by 2004, it had more than doubled to 0.128 per cent.
"Increasingly writing seems to follow forms which would have been confined to speech in 1980," say the researchers. "Whilst non-standard English is used much more frequently by candidates awarded lower grades, it is now also sometimes found in writing by candidates awarded highest grades." Examples include "dead good" for "very good", "real keen" for "really keen" and "gona" for "going to".
They conclude: "The influence of the general cultural climate outside schools is powerful.A wide range of phrases the examiners of 1980 would probably have frowned upon have become much more common."