English Sensei is a GPT designed as an interactive language tool for English learners, particularly for those who are Japanese speakers. This GPT is built to function within the ChatGPT ecosystem, augmenting the capabilities of its host. It provides an immersive environment for practicing spoken English and supports users with explanations on grammar and language usage in Japanese. Apart from that, it offers advice and guidance on the methods of English learning based on the individual needs of the users. This GPT employs a conversational approach that encourages learners to ask questions in English, giving them an opportunity to learn by doing. Starter prompts are provided to initiate and aid the discussions, particularly addressing specific lexical and grammatical issues, such as differentiating between similar words or the pronunciation and meaning of certain English terms. Another important feature of English Sensei is its flexibility: it can be utilised by users of varying English proficiency levels, meeting different learning objectives. Moreover, it can be accessed by users who have subscribed to the ChatGPT Plus plan. Overall, English Sensei offers a unique, personalized, and contextual learning experience that can significantly aid in English language acquisition for Japanese speakers.