Back again, with a new tutorial.
In this tutorial I'll show you one method I've found to making a Formant synth with 3xOsc.
First off, you'll need to add a 3xOsc channel, and link it to a mixer track.
In this tutorial I linked it to channel track one.

For the sake of simplicity, I'm going to use a single Square wave in 3xOsc set to -24 semitones.

Next, you need to click on the INS tab, then on the CUT subtab, in this screen you need to change a few knobs/buttons.
Envelope:
Enable envelope
AMT to the first line going clockwise.
ATT half way between the first and second line going counter clockwise
HOLD to the last line going clockwise.
DEC, SUS, and REL to the last line going counter clockwise
Filter:
MODX to the last line going counter clockwise.
MODY to the second line going clockwise.
Filter type LPx2

Now you're done with the 3xOsc bit, now to the mixer.

You'll want to add a Bitcrusher VST to slot one, in this tutorial I use
CMT Bitcrusher
Bring the downsampling down to 12x and you're done, EQ, tweak, etc to your desire.
Notes:
Higher ATT = Longer speech time
Lower downsampling means a higher voice, higher makes it lower.
You may want to up the high end a little in the mixer to get a more crisp sound.
This Synth sounds best on C4
More complex waveforms can be used.
Unrelated sidenote:
If anyone has any requests for tutorials, I'll do my best to make a tutorial for what you ask.