Hello Cecilia,
You can check the words in a dictionary as John suggested. To read articles or any material quicker,you have to practice reading , spelling ,writing on a regular basis. The more you practice ,the quicker your ability to read will become.You will start by making mistakes which is normal at a stage and gradually you will sense an improvement .You can use audio supportive material online and repeat the sentences in the passage so that you pick up the correct pronunciation . Your tutor or native speaking friend could help correct your mistakes .So good luck :)