Almost how waving to say hello/goodbye was to show no weapons to another, there is a possibility that some early humanoids spoke with a type of math. Having no words: fists, fingers, rocks, pebbles, twigs, straw or even motions could have been used to talk to one another.
Imagine a humanoid gathering nourishment when another humanoid is seen. Pretend that over time, they become acceptable to each other, then let's say one day another humanoid is seen by one of the mentioned two humanoids. The humanoid returns to the little nest or even just goes to the other humanoid to inform the other. Now, how did they talk?
The humanoid that saw the new humanoid is Hu1;
The companion humanoid is Hu2;
The new humanoid is Hu3.
Hu1 touches or makes a small snap/clap/sound to get Hu2's attention.
Hu1 uses a stick/twig/straw/fingers/lines to explain Hu1 & Hu2 to Hu2.
A rock or fist is used to explain their home or current position. Dots & pointing explain other locations.
So how does Hu1 explain this situation to Hu2? Here's a broad example:
Hu1 taps themselves and raises one finger.
Hu1 taps/points to Hu2 and raises a second finger.
Hu1 points in the direction they saw Hu3 and they raise a third finger.
Hu2 would probably realize this means another is near or in that one direction.
Hu1 could have used one hand or two, one for each of them Hu1;Hu2, Hu1 removes one finger from one hand, adds it to the other. Hu1 then could have used their second hand again to raise a finger for Hu3; Hu1 could have then used that same hand (the one with the finger that represents Hu3) to point in the direction of Hu3. Hu1 could have drawn in the ground or placed objects (sticks/twigs) in their hand to also explain the same situation.
To you this may not be a big deal but to Hu2, that third finger would have been the equivalent to a horror story. Hu1 & Hu2 may not be discussing pi to the furthest yoda nor are they even discussing an answer, they are talking using basic addition and subtraction. The visuals and the sounds/tapping/pointing was all the explanation most humanoids probably would have been able to understand at that time.
Everything started easy and simple sounds, lines, objects, shapes, addition, subtraction. Communication only becomes more complicated once the easy and simple is used up. Now that you've thought of all this I'll just add one comment for thought, "how much discussing do you think can be done in 60 million years?"