[Manuela]

I alsofind that most of the mistakes have as their source the kids' native language.
Greek learners have problems pronouncing "treasure" "join", they have difficulty understanding the diference in pronunciation between "sip" and "ship" since "s" and "sh" are interchangeable in Greek, without triggering any change in meaning.
Greek students have to learn to introduce themselves as:"I'm Mary" not "I'm the Mary" and they confuse the simple present with the present progressive forming a mixture of both that produces utterances of the type"Where are you live?" "I am live in Athens." I have to work really hard to get students to get rid of this "new" tense.