It is an easily acquired accomplishment to work out very complicated problems, approximately.
For example. What is 999 times one million and one?
Answer. About a thousand million.
What would you like estimating? Grains of sand in the Sahara? Drops of water in the Atlantic? How about; how many words have been spoken by all the people in the world in the last 1000years?
Say there are four billion people in the world now.
Say there were about one billion a thousand years ago.
Average people in the world during the last thousand years, two billion.
How many words does each person speak in a day?
Say two words a second. A Politician or businessman might speak for three hours a day, and halve that for the other person talking and you have the following......2x60x60x3 equals, say 20,000 divided by 2 is 10,000.
So we have ten thousand words a day for a talker. For a lonely Nepalese hill farmer without even an Ox to talk to, he might speak 500 words a day. There are many more peasants than captains of industry so average it out at 1,500 words a day per person.
Multiply 1,500 words a day by the number of people, 2,000,000,000 and multiply that by the number of days in 1000years, say 350,000.
Seems a bit complicated still does it? Alright do rounding up and down
Say 1,000,000,000 people at 2,000 words per day, answer two thousand billion words, easy. Multiply that by the days, 350,000 rounded up to 500,000 because we rounded down the population pretty severely.
Now 500,000 times two thousand billion. Easy again, halve the two to one and add six noughts......1,000,000,000,000,000
One million billion words have been uttered in the last thousand years. Approximately.
You dont agree? Didnt take your wife/husband/partner into account? Alright you work it out your way.
Happy New Year
Peter 
RE: Approximating.
Dear Peter,
This is a lovely post, but your approximations are a bit on the wild side according to myGoogle search, so I'm going to offer my own guesstimate. For instance Wikipediasuggests that in 1802 there were 1 billion people, and that current estimates are in excess of 6 and a half billion world-wide[link= http://www.unfpa.org/6billion/ ]http://www.unfpa.org/6billion/[/link]
So quite amazingly, if this is anywhere near the truth,we've come from a billion to 6 and a half billion (6,567,299,797 by the beginning of Feb)in a couple of hundred years.
Altogether approximately 106 billion people have been born.
Number of words spoken in a day [link= http://www.guardian.co.uk/g2/story/0,,1957827,00.html ]http://www.guardian.co.uk/g2/story/0,,1957827,00.html[/link]
gives us women 20,000 words a day compared with 7,000 for the average man. (This is of course an approximation and the Guardian article challenges it.). But you could average this out to 10,000 between the two sexes (there are more women than men, and quite a few very chatty men: I was with one the other night who wouldn't shut up, and he completely skews the figures).
Average Life Span. I give us 30 speaking years, as an average, for all these human beings- it may well be less.
All the words ever spoken. 30( av life span) x 10,000 (av number of words per day) x 365 (days in year) x 106, 000,000,000 (people who have ever lived). My calculator wouldn't do the maths. Google came up with this 30 * 10 000 * 365 * 106 000 000 000 = 1.1607 × 1019
and I don't know what that would look like, but it would sure make a din!
Sharon