Students make a genuine mistake because don’t actually know the correct form. The error is made due to factors such as trying to produce something which has not been fully learnt or learnt incorrectly, interference from L1, mistaken beliefs about the L2 rules. Students are not usually able to self-correct errors
Why do we make mistakes?
Interlanguage – A stage in learning in which Students mix elements of L1 structure, rules or pronunciation with L2 when they use L2. This is constantly changing as learners progress in L2 (I no come)
Mother-tongue interference – Applying the rules of L1 to L2 (The news are good)
Carelessness – Not paying attention
NB! This could be also due to tiredness or interlanguage