The Second Edition of the Oxford English Dictionary (OED) contains full entries for 171,476 words in current use, and 47,156 obsolete words. To this may be added around 9,500 derivative words included as subentries, bringing the total to 180,976. Subtracting the archaic words leaves us with about 133,826 current words.
Over half of these words are nouns, about a quarter, adjectives, and about a seventh, verbs; the rest is made up of interjections, conjunctions, prepositions, suffixes, etc. These figures take no account of entries with senses for different parts of speech (such as noun and adjective).
Only 25% of the words in the English language are of native origin. Here is a list of the languages from which most of the remainder were borrowed from.
- Latin, including modern scientific and technical Latin: 28.24%
- French, including Old French and early Anglo-French: 28.3%
- Old and Middle English, Old Norse, and Dutch: 25%
- Greek: 5.32%
- No etymology given: 4.03%
- Derived from proper names: 3.28%
- All other languages contributed less than 1%
Of course, the OED, like all dictionaries, is just a sampling of the English lexical treasure, chosen by the editorial staff. As I have shown elsewere, the words of a language cannot be counted. However, the percentages are telling testimony of the English obsession with borrowing. (Source: the OED itself, of course.)