The 4th Speedlang Challenge was the first one that I organized. It took place from February 20, 2019 to March 3, 2019.
The phonology had to show a three-way phonation contrast, have either less than four or more than six vowels, and include an archiphoneme. The language had to have reduplication, but otherwise no concatenative morphology. It also had to make an animacy distinction somewhere in the grammar and divide word classes differently than English. You can read the full requirements here.