Pupils` ability to learn and develop knowledge depends largely upon their literacy skillset. All school subjects have a certain language set that connect words and concepts to knowledge. It is necessary for the pupils to grasp the language set in order to be able to make sense of instructions, educational books and general teaching that goes in the classroom. In school science subjects will be challenging for pupils because of new vocabulary and large amounts of technical terms and factual texts. Pupils with reading and writing difficulties are heavily affected in their schooling but not because of lack of intelligence. But due to difficulties in decoding and producing texts, these pupils have a disadvantage in the scientific language. In order for teachers to create suitable teaching strategies, knowledge is important in how and more precisely where the difficulties in the scientific subject can be an obstacle. Pupils with reading and literacy difficulties have a phonological problem with matching sound with words. With help of repetitional phonological training that gradually advances the pupils can improve their phonological awareness and thereby reading and writing. Teachers that acknowledge the importance and the process of working with developing the scientific language in the school subject can help all children attending in class. Strategies as organizing communicative exercises and activities, evaluating continuously with the student, and studying meaningful topics from the pupils everydaylife to activate the pupils in the necessary language, in order to develop knowledge.