A person who doesn't speak English fluently is often referred to as a "non-native English speaker" or simply an "English language learner" (ELL). These terms are used to describe individuals who are still in the process of learning English as a second or additional language and may not have achieved full fluency yet. It's important to use these terms respectfully and without any negative connotations, as language proficiency can vary widely among individuals, and being a non-native English speaker is not indicative of a person's intelligence or abilities.