One of the characteristics that Greek learners have when speaking English is their use of "ahhh" as a filler. Basically, a filler is a sound or phrase that a speaker uses to "fill in" gaps in his/her speech so as to show their listener that they haven't finished speaking yet and so keep their turn going. In English we use things such as "uhmm", "you know", "well" etc. to do this. In Greek people often use "ahhh" either on its own or attached to to the end of the last word spoken. An extreme example of this would sound like this,
Iahh wouldahh likahh to ahhh talkahhh about ahhh the ahhh exam.
This can make their English hard to understand (as the individual words tend to merge together) and, of course, it makes it hard to figure out when they've actually finished speaking and so when it is ok to speak yourself.
The problem is that the vast majority of students have no idea that they are doing this and so continue to make the same mistake. Whilst endless hours are spent working on grammar and vocabulary, little, if any time is spent on pronounciation practice in most lessons.
Here is an exercise that helps students tackle this by making them aware of their own voice.
1 Explain to students that we're going to play a speaking game. All they have to do is speak for a long as they can about an everyday subject e.g.
2 Choose a volunteer (preferably somebody who is not shy about talking in front of the others).
3 Tell them that this game has just one rule; that they must speak as long as they can without saying "ahhh". You may need to demonstrate what you mean as most students are unaware that they even use this expression in their speech.
4 Time the student and allow them to speak. On average most students doing this for the first time last less than 10 seconds. It may even be a good idea to record them (using, say a mobile phone) as often the students will vehemently deny that they used "ahhh". The use of the sound is so deeply ingrained that we fail to register it as unusual or wrong. It is only when they hear the recording that they realise they've been using it.
5 Now explain to the students what a filler is and how in English the same job is carried out by other sounds or expressions e.g. "uhmm", "you know" etc. Show them how to use the English fillers.
6 Now ask the student who volunteered to have another go at the game, this time using English rather than Greek fillers. You should see a marked improvement.
7 Students play the game in pairs, each one timing (and, if possible, recording) the other.
8 Swop roles a few times.
You need to explain to the students that such deeply ingrained mistakes do not disappear overnight. However, as they have realised that there is a problem, solving it becomes much, much easier. Also make sure they understand that just by substituting a couple of sounds their English will be much more natural.