How can an English language teacher intend to teach, especially since she neglects it despite her fluency and love for it, even though she is not good at translation?

Learning the English language with the intention of transferring useful modern technologies to Muslims, or translating beneficial books for them, or translating Islamic books and inviting to Islam through them, or contributing to the translation of Islamic websites and da'wah projects for communities, or to be a good role model by your commitment to religion alongside your proficiency in the language—all these are good intentions for which you will be rewarded.