With technology playing a growing role in language education, tools that adapt to learners’ needs can make practice more effective. AdaptLingo is a speech-based chatbot designed to help English learners improve their speaking skills through natural conversation. Learners speak directly to the chatbot, which listens to their speech and determines their English proficiency—beginner, intermediate, or advanced—and then adjusts its responses to match their level. Beginners receive simpler language and slower speech, while advanced learners engage in more natural, fluent conversation. To ensure responses are appropriate for each level, AdaptLingo selects words from a well-established vocabulary list suited to the learner’s proficiency, reinforcing level-appropriate language learning. The chatbot also adjusts its speaking speed to make conversations more accessible or challenging, depending on the user’s ability. By offering a fully speech-to-speech experience, AdaptLingo provides a personalized and interactive way for English learners to practice speaking in a low-pressure environment. This tool will be open-source, making English conversation practice more accessible to learners everywhere. AdaptLingo is a technological innovation that will be integrated into classroom environments to supplement students' curricula, supporting English learners from diverse native language backgrounds with additional speaking practice.