How common is it to confuse "Justin" with "Jason"?
I only ask because three separate professors I work with have done it.
It makes sense, because the two share three letters and an ending rime, [In]. Additionally, even though the "t" is missing in Jason, both have the stresses on the first syllable, and so the last part is sort of rushed out anyway.
And you would think that "a" and "u" would have distinct enough sounds, but in actuality, if you test it out, with the initial "J", both vowels are created with a lower front tongue and high back tongue. The only (slight) difference in the vowels are the result of a shifted middle part of the tongue. Try it out!
This is where I would include more specialized terms from Linguistics to impress my legion of dedicated readers, however I've gone blank on some of the jargon associated with vowels, so I will stop while I'm ahead.
I guess my conclusion from all of this is that words may be closer in sound than they may seem from how they are written. Which I already knew. So this is just another anecdote to support that conclusion.