Quick now, what's the most common non-Germanic word in the English language? The most common non-Germanic noun? Verb? Preposition? The most common word from Greek? From Celtic? From Indic? From a non-Indo-European language? While you were thinking I decided to examine the "Word Frequency Book" by John B. Caroll and other to discover the answers to some of these questions. Keep in mind that Carroll's book is based on writing, not speech, in American English. Since Carroll does not distinguish among homographs, I also consulted W. Nelson Francis's and Henry Kucera's "Frequency Analysis of English Usage" to ascertain the commonest verbs, nouns, etc. This book is derived from Kucera and Francis's "Present-Day American English", which can be compared with Carroll from overall word-frequencies (not distinguished among parts of speech). Not surprisingly, these tow references disagree to some extent as to what the commonest words in English may be.
Wilson, Robert J.
"Comments on Some Common Words,"
Word Ways: Vol. 21
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol21/iss3/8