>Are you measuring by fraction of words in a word list, or fraction of words in a typical utterance?

I think he's measuring the first, which gives a skewed picture, the latter is why english is considered a germanic language. The core of the language is all germanic words and you can still get by reasonably well without using any of the french/latin additions. Generally if a word is smaller and less 'fancy' it's of germanic origins, if it's longer and 'fancier' it's probably of romance origins.