I remember studying Armenian language. It had three sounds that initially sounded almost the same to me. They were all something like /tz/ or /ts/ No English words begin with those sounds, so English speakers don’t recognize the difference. In Armenian, however, those three little sounds make as much difference as the sounds /b/, /p/, and /k/ do in English. Bit, pit, and kit are all different words in English, so it is important to get that first sound right. Same thing in Armenian with those /ts/ /tz/ sounds–if you change the sound, you change the word. The problem is, it’s hard to produce different sounds if you can’t even *hear* the difference between sounds!
When you were born, your brain could perceive (or hear) all the sounds of all human languages. Very quickly, however, you learned to pay attention only to the sounds that people around you produced–the sounds that are important for the language(s) YOU heard. If you only heard one language while you were a baby, then your brain is really good at hearing and distinguishing the sounds of that one language. Unfortunately, this means that maybe it isn’t so good at hearing sounds from unfamiliar languages. Luckily, and with practice, you can be trained to distinguish sounds from other languages. This is called perception training.
Research shows that perception training helps improve pronunciation in a foreign language. In fact, you should first be sure you can hear the differences between sounds before you work on producing the sounds.
Here’s a good (and free!) online tool for doing perception training in English: English Accent Coach.
You can work on vowels or consonants using the activities on this website. For consonants, you choose the sounds you want to work on. For example, if you have a problem hearing the difference between /L/ and /R/ and /N/, with English Accent Coach, you set up a ‘game’, and choose those three sounds. A voice produces one of the sounds, and you click on what you hear. The ‘game’ tells you if you are correct or not. I wish they actually said words, but they don’t. They produce only the sound, but still, it looks like a good tool for perception practice.
Go check it out!