LSTM means Long-Short Term Memory so the reason why we are using this type of train about AI. It is because we train machine like a baby. We are giving short term information and long term information that it will remember when to use what information. LSTM is the one of Deep Learning part. It belongs to RNN(Recurrent Neural Network). If you interested with Deep Learning this project will give you some idea. With pleasure you can also check my github account for codes if you want more information.