The first singularity would have to have been the ability to recognize the patterns in the world (which is a part of speech), things like we can run longer than prey, holding stick can reach farther, this rock is harder skull, attach rock to stick, hitting rock against rock makes sparks, sparks make fire, fire makes light, food tastes better after being near fire, etcetera. Admitably animals can also do this, humans just bring it up by several levels.
There is only one Truth, but there are many ways to perceive it
Language had to have been the first singularity, as it's necessary for pretty much everything. For example, thoughts. Anyone who has ever had a thought, they had to think words. Try it! If you think, you hear words in your head. The words will be in whatever language you speak, as words, along with images, are necessary for thoughts to exist. True, animals can "communicate" with each other, but it is extremely limited to mostly just expressing "Hey this is my territory". That's pretty much it. People have vocabulary, so we can have complex conversations, something organisms without language can do.