Final answer:
The correct option is didn't use. The past simple tense is used to talk about past actions or states. In this case, the speaker is referring to their ability or inability to speak English when they were 5 years old.
Step-by-step explanation:
The correct option is didn't use. In English, we use the past simple tense to talk about actions or states that happened in the past. In this case, the speaker is referring to a specific time in the past (when they were 5 years old) and their ability or inability to speak English at that time. The correct form of the verb in the past simple tense is 'didn't use'. The other options are grammatically incorrect or do not fit the context.
Learn more about Past simple tense