I have done lots of investigating in this case. And there are different approaches to making a talking sounding dubstep bassline. I like to think of them as monster sounding.
One common sound, that is not very impressive imo, is one that was first made popular in Skrillex Cinema.
This is done with a saw wave with a low pass filter with a cutoff set very low, with a very high resonance setting. Then apply apply a bit reduction effect. Skrillex and everyone else use Ableton's redux.
Then there are more general talking sounding synths. I can explain to you how I created the one I use in this track and this track (with lessened effect) In these tracks I did not aim to make it exceptionally pronounced, but you certainly can with this approach.
I like to call it the duelling band-pass filter approach. And depending how wet you want to apply it to the track, can very much give talking properties to it.
Basically you want to apply two band pass filters to your synth track. One with a cutoff in the lower frequencies. The other with a cutoff in the upper frequncies. You want them to independently modify the synth and have their outputs mixed. So if you use Ableton you would have them both in an effect rack in separate chains. I don't know how you achieve this in other DAW, but you don't want them running in series (eg the second bandpass is working on the first bandpass' output. Rather you want the both working in parallel, each getting the clean synth input, and then mixing their output.
Then you have to modulate the cutoff point of the duelling bandpass filters in opposite directions. You could do this with track automation, or you could map each cutoff to a single knob on a midi controller. Then edit the mapping to invert the direction and modify the range of the parameter.
Change the cutoff point of the low filter so at the start it is around 100hz and at the end position it is around 600hz. Then with the other high bandpass filter, at the start position you want the filter to be at like 15khz and at the end position you would want it to be at around 2khz.
Does this make any sense? The bandpass filters move in unison, across different frequency ranges, in opposites directions. So when the low band pass is low, the high band pass is high, as the lower bandpass moves from low -> upwards, then high bandpass moves from high -> downwards.
Then you can vary the pitch as you manipulate these two filters with great effect.