There are various alternatives to the phrase "non-native speaker" that can be used to describe someone who speaks a language other than their first language. One of the commonly used synonyms in this context is "second language learner," which describes an individual who is learning the language but is not a native speaker. Another synonym for "non-native speaker" is "ESL learner," where ESL stands for "English as a second language." "Foreign language learner" is also an option that can be used to describe someone who is learning a language that is not their mother tongue. Other phrases that can be used in place of "non-native speaker" include "multilingual speaker" and "bilingual learner".