John Humphrys, the presenter of Radio 4's Today programme, can strike fear into prime ministers and CEOs. But he was no match for Oxford University classicist Cressida Ryan in an interview this week.
In an interview to mark Grammar Day Mr Humphrys asked whether English words which sound as if they are derived from Latin should take Latin plural endings, for example bacteria rather than bacteriums and referenda rather than referendums.
Dr Ryan said: 'There are three issues here: what is correct Latin? What is correct English? What is the relationship between those two? It depends whether you are using something as a Latin word you have borrowed, or if you are choosing to use it as an English word.'
Dr Ryan pointed out that English is a living, flexible language that can accommodate different ways of expressing the same word. She said: ‘People in particular technical business will use words in a particular way for them that might different from people in other parts of the country because English is a language which has regional dialects, temporal dialects, and describes different things in different ways.
‘So it is fair to use bacterium in the singular form. But if you wanted to talk about a class of things then bacteria sounds perfectly fair as a collective noun.
'The more Latin you do at school or university, the more you realise how quickly linguistic change happens and how dynamic languages are.'
Dr Ryan pointed out that the collective wisdom about how a word should correctly be written is often wrong. 'For 'syllabus', actually the plural in Latin would still end in 'us' but most people think it would be syllabi,' she said. 'In Italian, panino would be the singular of panini, but in the UK we use panini as the singular when ordering in a restaurant.'
She then added: 'There's one other aspect to this, which is that bacteria is in fact singular and a Greek word.'
To the sound of background laughter in the studio, Mr Humphrys could only reply: 'Ah. You’ve silenced me.'
Listen to the full interview here.