A schoolboy error in The Telegraph

Yesterday's Telegraph included an article by David Crystal about covering the history of English in 100 words. It's a fascinating piece but totally spoilt by its last sentence:

'If a present-day Dr Who were to travel back to AD 449, when the first Anglo-Saxon boats arrived, his biggest issue would not be alien monsters, but getting the Anglo-Saxons to understand his alien words.'

Oh dear, oh dear, oh dear; as everybody should know, the Doctor would have no problem making himself understood and indeed understanding what was being said to him, being as the TARDIS has a universal translator function that translates for every occupant of the TARDIS.