Great question from Attila at The Challenge of Learning English:  
“I have a question about two phrasal verbs:  settle on and settle down.
Is there any difference into the pronunciation of these:
settled on  
settle down
settled down
Or move on – move down:
moved on
move down
moved down
But I guess, the difference can be very slight,  hardly recognisable so only the context can help. Is it true?”
The big difference in phrasal verbs is the stress.  Stress the SECOND word (in compound nouns, stress the FIRST).  Also keep in mind that these words must be linked with no pause between them.

There are sound differences in the words, of course.  The hardest to hear would be with the -ED ending.  The reason for that is because of the word DOWN.  The last D in the -ED ending links to the D in DOWN.  There is a slightly longer D in settled down and moved down.  A native speaker can hear this subtle difference.
In the ON example, the vowel is very different than in DOWN.
settle on:  s-e-d-l-o-n
settle down:  s-e-d-l-d-ow-n
settled down:  s-e-d-l-d-d-ow-n
So, no context is not needed for a native speaker.
You can check out my free class on word stress on YouTube for more information.