English because it is a little bit of all languages. (Especially American English, which is quite different than anywhere else)

Probably the English language, both because it is spoken by such a wide range of people and because it has historically been very willing to steal words from other languages.

Trading languages have bigger vocabularies than insular languages. English is a good example of a trading language. It is basically Anglo-Saxon in grammar and vocabulary, but has absorbed over half its vocabulary via Latin based languages (such as Latin itself, French, Italian and Spanish). Through its mercantile and eventual colonial links, it has absorbed vocabulary from all over the world. I would hazard a guess that English would have one of the largest, if not the largest vocabulary, as it has never had a central body regulating its vocabulary (as has had French). ANother language with an enormous vocabulary is Malay/Indonesian. Like English, it was a trading language, used , in medieval times, from Indonesia to China, and to the Middle East. It is basically an Austronesian language, but, because of the religous and cultural history of the islands, has absorbed large amounts of vocabulary from Sanskrit, Tamil, ARabic/Persian, Dutch, and English. Because of the hundreds of regional languages in the islands, Indonesian has also absorbed regional vocabulary. http://www.cs.tut.fi/~jkorpela/lang/vocab.html discusses the topic This site:http://members.aol.com/DrHumph/funetik.htm suggests that English has the largest vocabulary, over three times as large as other languages. Likewise, www.hello-online.ru/knowhow.php?comid=70 says that English has 500 000 regular words and and extra 300 000 technical words. www.rio.maricopa.edu/distance_learning/tutorials/study/vocabulary.shtml suggests over 1 million words in English This may be true. However, I wonder if, in fact, it is accurate to the extent that English has had much more dictionary work done than, say, a language like Indonesian, which has a very large vocabulary ( I can speak it. I have been studying it for over 30 years and I have not yet begun to get to the depths of the vocabulary available for use. There are not many good dictionaries, certainly nothing of the calibre of the OED, which is an ongoing project. Most of us in the field, still use the Dictionary set by scholars Echols and SHadily which came out in the 60s, with more recent revisions, but Indonesian has undergone immense changes since then, and I doubt that 1/4 of the words used by average indonesians are found in E&S.

Greek is the right answer. The 30% and more of English words are Greek or have Greek origin.