I keep making attempts to help L2 English learners break their strange pronunciation habits with tools like phonetic charts, but it seems like they just relapse. One of the big issues I deal with with L2 English learners in Japan is that they finish words with "o". For example, instead of saying, "Can you get me that?" They say, "Can you geto me thato?" They're trying to enunciate.
I have a controversial way of teaching pronunciation that ends with consonants that seems to be effective, but people just relapse into the behavior of enunciating with the added o. One of my regular students often uses count pronouns with non-count words and says, 'It's a style of English speaking. So, it's okay.'
Let's look at a specific example: walk vs. work. If you have people sound out 'werk' and 'wok', they sound spot-on. Unfortunately, after about 5 minutes, they're right back to saying "WAHELK" and "WHORLK", which just sounds terrible.
How can I solidify their pronunciation?