Many of my clients complain that they are not making progress.  They say “people still can’t tell the difference or understand me!”

True. Not yet.

The problem is that speech is a complex skill. In order to be able to use new sounds during conversation, you must move through a hierarchy of difficulty:
1. Say the sound alone
2. Say the sound in a word
3. Say the sound in a phrase
4. Say the sound in a sentence
5. Say the sound while reading aloud
6. Use the sound in “structured” conversation
7. Use the sound in normal conversation

My clients usually begin to use some sounds in conversation after a month of training.  Be patient and practice. People will notice the difference.