Prerna is attempting to spell a word using her own intuitive knowledge of the spelling system and sounds of her language. Which term best describes this educational phenomenon?

Sumit (age 3), his brother Malay (age 6), and their parents recently moved from Jharkhand to Mumbai. The family has never used English to communicate before. In an effort to acquire mastery over English more rapidly, they decide to converse only in English daily. However, they are exposed to a lot of colloquialisms and grammatically incorrect language inputs at home. Both children are now struggling with language tasks at school. What could be the primary developmental reason?