I've tracked all my son's first words since birth [OC]

Reddit user jonjiv conducted a case study in human language development. He carefully monitored his son's speaking ability, and here is what he found:

https://imgur.com/gallery/KwZ6C#qLwsn9S...go to this link for a clearer picture of the chart!

How to use in class:
1) Good for Developmental Psychology. Look at that naming explosion!
2) Good to demonstrate how nerdy data collection can happen in our own lives.
3) Within versus between subject design. Instead of sampling separate 10, 11, 12, etc. month old children, we have real-time data collected from one child. AND this isn't retrospective data, either.
4) Jonjiv even briefly describes his "research methodology" in the original post. The word had to be used in a contextually appropriate manner AND observed by both him and his wife (inter-rater reliability!). He also stored his data in a Google sheet because of convenience/ease of tracking via cell phone.