Max's vocabulary started exploding around 15-17 months old. I started writing down everything he could say (with understanding of what it means) starting at 18 months, when he could say 107 words. I stopped when he hit 1000 words, a day before his second birthday. During that time, he learned an average of five words a day. Here's the graph:

I did kinda want him to hit 1000, so I spent extra effort teaching him words in the last nine days.

Out of the 1000, he knew 248 Chinese words, 738 English words, and 14 words in other random languages. He learns most of his Chinese words from me, and some at daycare. I speak mostly Chinese to him, but it's not natural for me, so sometimes I switch back to English, plus Chloe speaks all English to him, which is why his English is way ahead.

What kind of words does he know?

I always love it when people share revenue data for their apps / games / books / works, and it's been four years since The Motivation Hacker came out, so here's another updated graph of ebook sales by platform including the second year. (See also Second Year Book Sales, First Year Book Sales, Aftermath: The Motivation Hacker)

I forgot about checking the numbers for year three, and now it's been just over four years, so I thought I'd take another look. Looks like sales have more or less held steady on Kindle and the other ebook platforms, but CreateSpace paperbacks have come out of nowhere, so year four was better than year three or even two. Cool! (CreateSpace paperbacks cost more than ebooks, $7.99 to $2.99, but I set it so that the royalty is the same either way, about $2.21.)

Ratings kept falling on Amazon, from 4.4 two years ago to now 4.1. Goodreads inched down from 3.85 to 3.81, with a combined total of 633 ratings. I wrote the book quickly (about 200 hours total) and have now made about $17K, or around $86/hr. Not a huge amount, but not bad for something that I initially thought only 50-100 people would read.